getimagesize

(PHP 4, PHP 5, PHP 7, PHP 8)

getimagesize — Get the size of an image

Description

getimagesize(string $filename, array &$image_info = null): array|false

The getimagesize() function will determine the size of any supported given image file and return the dimensions along with the file type and a height/width text string to be used inside a normal HTML IMG tag and the correspondent HTTP content type.

getimagesize() can also return some more information in image_info parameter.

Caution

This function expects filename to be a valid image file. If a non-image file is supplied, it may be incorrectly detected as an image and the function will return successfully, but the array may contain nonsensical values.

Do not use getimagesize() to check that a given file is a valid image. Use a purpose-built solution such as the Fileinfo extension instead.

Note: Note that JPC and JP2 are capable of having components with different bit depths. In this case, the value for "bits" is the highest bit depth encountered. Also, JP2 files may contain multiple JPEG 2000 codestreams. In this case, getimagesize() returns the values for the first codestream it encounters in the root of the file.

Note: The information about icons are retrieved from the icon with the highest bitrate.

Note: GIF images consist of one or more frames, where each frame may only occupy part of the image. The size of the image which is reported by getimagesize() is the overall size (read from the logical screen descriptor).

Parameters

filename: This parameter specifies the file you wish to retrieve information about. It can reference a local file or (configuration permitting) a remote file using one of the supported streams.
image_info: This optional parameter allows you to extract some extended information from the image file. Currently, this will return the different JPG APP markers as an associative array. Some programs use these APP markers to embed text information in images. A very common one is to embed » IPTC information in the APP13 marker. You can use the iptcparse() function to parse the binary APP13 marker into something readable.

Note:
The image_info only supports JFIF files.

Return Values

Returns an array with up to 7 elements. Not all image types will include the channels and bits elements.

Index 0 and 1 contains respectively the width and the height of the image.

Note:
Some formats may contain no image or may contain multiple images. In these cases, getimagesize() might not be able to properly determine the image size. getimagesize() will return zero for width and height in these cases.

Index 2 is one of the IMAGETYPE_* constants indicating the type of the image.

Index 3 is a text string with the correct height="yyy" width="xxx" string that can be used directly in an IMG tag.

mime is the correspondant MIME type of the image. This information can be used to deliver images with the correct HTTP Content-type header:

Example #1 getimagesize() and MIME types

<?php
$size = getimagesize($filename);
$fp = fopen($filename, "rb");
if ($size && $fp) {
    header("Content-type: {$size['mime']}");
    fpassthru($fp);
    exit;
} else {
    // error
}
?>

channels will be 3 for RGB pictures and 4 for CMYK pictures.

bits is the number of bits for each color.

For some image types, the presence of channels and bits values can be a bit confusing. As an example, GIF always uses 3 channels per pixel, but the number of bits per pixel cannot be calculated for an animated GIF with a global color table.

On failure, false is returned.

Errors/Exceptions

If accessing the filename image is impossible getimagesize() will generate an error of level E_WARNING. On read error, getimagesize() will generate an error of level E_NOTICE.

Changelog

Version	Description
8.2.0	Now returns the actual image dimensions, bits and channels of AVIF images; previously, the dimensions were reported as `0x0`, and bits and channels were not reported at all.
7.1.0	Added WebP support.

Examples

Example #2 getimagesize() example

<?php
list($width, $height, $type, $attr) = getimagesize("img/flag.jpg");
echo "<img src=\"img/flag.jpg\" $attr alt=\"getimagesize() example\" />";
?>

Example #3 getimagesize (URL)

<?php
$size = getimagesize("http://www.example.com/gifs/logo.gif");

// if the file name has space in it, encode it properly
$size = getimagesize("http://www.example.com/gifs/lo%20go.gif");

?>

Example #4 getimagesize() returning IPTC

<?php
$size = getimagesize("testimg.jpg", $info);
if (isset($info["APP13"])) {
    $iptc = iptcparse($info["APP13"]);
    var_dump($iptc);
}
?>

Notes

Note:
This function does not require the GD image library.

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User Contributed Notes 24 notes

down

james dot relyea at zifiniti dot com ¶

15 years ago

As noted below, getimagesize will download the entire image before it checks for the requested information. This is extremely slow on large images that are accessed remotely. Since the width/height is in the first few bytes of the file, there is no need to download the entire file. I wrote a function to get the size of a JPEG by streaming bytes until the proper data is found to report the width and height:

<?php
// Retrieve JPEG width and height without downloading/reading entire image.
function getjpegsize($img_loc) {
    $handle = fopen($img_loc, "rb") or die("Invalid file stream.");
    $new_block = NULL;
    if(!feof($handle)) {
        $new_block = fread($handle, 32);
        $i = 0;
        if($new_block[$i]=="\xFF" && $new_block[$i+1]=="\xD8" && $new_block[$i+2]=="\xFF" && $new_block[$i+3]=="\xE0") {
            $i += 4;
            if($new_block[$i+2]=="\x4A" && $new_block[$i+3]=="\x46" && $new_block[$i+4]=="\x49" && $new_block[$i+5]=="\x46" && $new_block[$i+6]=="\x00") {
                // Read block size and skip ahead to begin cycling through blocks in search of SOF marker
                $block_size = unpack("H*", $new_block[$i] . $new_block[$i+1]);
                $block_size = hexdec($block_size[1]);
                while(!feof($handle)) {
                    $i += $block_size;
                    $new_block .= fread($handle, $block_size);
                    if($new_block[$i]=="\xFF") {
                        // New block detected, check for SOF marker
                        $sof_marker = array("\xC0", "\xC1", "\xC2", "\xC3", "\xC5", "\xC6", "\xC7", "\xC8", "\xC9", "\xCA", "\xCB", "\xCD", "\xCE", "\xCF");
                        if(in_array($new_block[$i+1], $sof_marker)) {
                            // SOF marker detected. Width and height information is contained in bytes 4-7 after this byte.
                            $size_data = $new_block[$i+2] . $new_block[$i+3] . $new_block[$i+4] . $new_block[$i+5] . $new_block[$i+6] . $new_block[$i+7] . $new_block[$i+8];
                            $unpacked = unpack("H*", $size_data);
                            $unpacked = $unpacked[1];
                            $height = hexdec($unpacked[6] . $unpacked[7] . $unpacked[8] . $unpacked[9]);
                            $width = hexdec($unpacked[10] . $unpacked[11] . $unpacked[12] . $unpacked[13]);
                            return array($width, $height);
                        } else {
                            // Skip block marker and read block size
                            $i += 2;
                            $block_size = unpack("H*", $new_block[$i] . $new_block[$i+1]);
                            $block_size = hexdec($block_size[1]);
                        }
                    } else {
                        return FALSE;
                    }
                }
            }
        }
    }
    return FALSE;
}
?>

down

nikolam3244 at gmail dot com ¶

6 years ago

There's a code snippet for getting JPEG image dimensions by getting only first few bytes of the file, but it doesn't work for PNG files, so I wrote one. It will download only the first 24 bytes instead of the whole image, and thus being much faster than getimagesize() and it will save bandwidth at the same time:

<?php
// Retrieve PNG width and height without downloading/reading entire image.
function getpngsize( $img_loc ) {
    $handle = fopen( $img_loc, "rb" ) or die( "Invalid file stream." );

    if ( ! feof( $handle ) ) {
        $new_block = fread( $handle, 24 );
        if ( $new_block[0] == "\x89" &&
            $new_block[1] == "\x50" &&
            $new_block[2] == "\x4E" &&
            $new_block[3] == "\x47" &&
            $new_block[4] == "\x0D" &&
            $new_block[5] == "\x0A" &&
            $new_block[6] == "\x1A" &&
            $new_block[7] == "\x0A" ) {
                if ( $new_block[12] . $new_block[13] . $new_block[14] . $new_block[15] === "\x49\x48\x44\x52" ) {
                    $width  = unpack( 'H*', $new_block[16] . $new_block[17] . $new_block[18] . $new_block[19] );
                    $width  = hexdec( $width[1] );
                    $height = unpack( 'H*', $new_block[20] . $new_block[21] . $new_block[22] . $new_block[23] );
                    $height  = hexdec( $height[1] );

                    return array( $width, $height );
                }
            }
        }

    return false;
}
?>

down

tomasz at trejderowski dot pl ¶

11 years ago

If you want to "convert" value returned by "getimagesize()" as index "2" into something more human-readable, you may consider using a function like this one:

    $imageTypeArray = array
    (
        0=>'UNKNOWN',
        1=>'GIF',
        2=>'JPEG',
        3=>'PNG',
        4=>'SWF',
        5=>'PSD',
        6=>'BMP',
        7=>'TIFF_II',
        8=>'TIFF_MM',
        9=>'JPC',
        10=>'JP2',
        11=>'JPX',
        12=>'JB2',
        13=>'SWC',
        14=>'IFF',
        15=>'WBMP',
        16=>'XBM',
        17=>'ICO',
        18=>'COUNT'  
    );
    
    $size = getimagesize($filename);
    
    $size[2] = $imageTypeArray[$size[2]];

Or something similar.

down

php dot net at dannysauer dot com ¶

19 years ago

Note that, if you're going to be a good programmer and use named constatnts (IMAGETYPE_JPEG) rather than their values (2), you want to use the IMAGETYPE variants - IMAGETYPE_JPEG, IMAGETYPE GIF, IMAGETYPE_PNG, etc.  For some reason, somebody made a horrible decision, and IMG_PNG is actually 4 in my version of PHP, while IMAGETYPE_PNG is 3.  It took me a while to figure out why comparing the type against IMG_PNG was failing...

down

simon dot waters at surevine dot com ¶

9 years ago

Note: getimage size doesn't attempt to validate image file formats

It is possible for malformed GIF images to contain PHP and still have valid dimensions.

Programmers need to ensure such images are validated by other tools, or never treated as PHP or other executable types (enforcing appropriate extensions, avoiding user controlled renaming, restricting uploaded images to areas of the website where PHP is not enabled).

http://ha.ckers.org/blog/20070604/passing-malicious-php-through-getimagesize/

down

redcore at gmail dot com ¶

17 years ago

It's always good to check out an image's dimensions while attempting to upload to your server or database...especially if it's going to be displayed on a page that doesn't accomodate images beyond a particular size.

<?php

$tmpName = $_FILES['userfile']['tmp_name'];
        
list($width, $height, $type, $attr) = getimagesize($tmpName);

if($width>275 || $height>275)
{
die("exceeded image dimension limits.");
}

?>

down

utilmind ¶

13 years ago

Here is the function which determines whether the PNG image contains alpha or not:



<?php

function is_alpha_png($fn){

  return (ord(@file_get_contents($fn, NULL, NULL, 25, 1)) == 6);

}

?>



The color type of PNG image is stored at byte offset 25. Possible values of that 25'th byte is:

 * 0 - greyscale

 * 2 - RGB

 * 3 - RGB with palette

 * 4 - greyscale + alpha

 * 6 - RGB + alpha

down

info at alex-lawrence dot com ¶

16 years ago

Could be useful (didn´t know where to post it):

function getImageErrors( $filename, $type = "", $minWidth = 0, $minHeight = 0, $maxWidth = 0, $maxHeight = 0, $maxFileSize = 0 )
{
    $errors = array();
    if ( file_exists( $filename ) )
    {
        $ending = substr( $filename, strpos( $filename, "." ) );
        if ( is_array( $type ) )
        {
            $isTypeOf = false;
            foreach( $type as $eachtype )
            {
                if ( $ending == $eachtype )
                {
                    $isTypeOf = true;
                }
            }
            if ( ! $isTypeOf )
            {
                $errors[ 'type' ] = $ending;
            }
        }
        elseif ( $type != "" )
        {
            if ( $ending != $type )
            {
                $errors[ 'type' ] = $ending;
            }
        }
        $size = getimagesize( $filename );
        if ( $size[ 0 ] < $minWidth )
        {
            $errors[ 'minWidth' ] = $size[ 0 ];
        }
        if ( $size[ 1 ] < $minHeight )
        {
            $errors[ 'minHeight' ] = $size[ 1 ];
        }
        if ( ( $maxWidth > $minWidth ) && ( $size[ 0 ] > $maxWidth ) )
        {
            $errors[ 'maxWidth' ] = $size[ 0 ];
        }
        if ( ( $maxHeight > $minHeight ) && ( $size[ 1 ] > $maxHeight ) )
        {
            $errors[ 'maxHeight' ] = $size[ 1 ];
        }
        if ( ( $maxFileSize > 0 ) && ( filesize( $filename ) > $maxFileSize ) )
        {
            $errors[ 'maxFileSize' ] = filesize( $filename );
        }
    }
    else
    {
        $errors[ 'filename' ] = "not existing";
    }
    return ( count( $errors ) > 0 ? $errors : null );
}

down

Steve ¶

13 years ago

The list of defined IMAGETYPE_ constants is on the manual page for exif_imagetype:

http://www.php.net/manual/en/function.exif-imagetype.php

down

shmohel at gmail dot com ¶

16 years ago

Rather than making a lengthy function that essentially runs twice (once as width, once as height) I came up with a helpful function that uses variable variables to set a maximum height/width. Hope someone finds this helpful.

function scaleimage($location, $maxw=NULL, $maxh=NULL){
    $img = @getimagesize($location);
    if($img){
        $w = $img[0];
        $h = $img[1];

        $dim = array('w','h');
        foreach($dim AS $val){
            $max = "max{$val}";
            if(${$val} > ${$max} && ${$max}){
                $alt = ($val == 'w') ? 'h' : 'w';
                $ratio = ${$alt} / ${$val};
                ${$val} = ${$max};
                ${$alt} = ${$val} * $ratio;
            }
        }

        return("<img src='{$location}' alt='image' width='{$w}' height='{$h}' />");
    }
}

down

info at personalmis dot com ¶

16 years ago

Seems the various ways people are trying to proportionaly scale an image, up or down, could be more straight forward if one remembers ones algebra.

The formula is, y = mx, where m is the slope of the line. This is the ratio of y:x or m = y/x.

So if...

// max values for x and y
$y_max = 600;
$x_max = 800;

// image size
$y1 = 2000;
$x1 = 3000;

// use width for scaling
if ($x1 > $x_max)
{
    // find slope 
    $m = $y1/$x1;
    // set x side to max
    $x2 = $x_max;
    // set y side to a proportional size
    $y2 = $m * $x1;
}

The new image proportionally scaled will be x2 = 800, y2 = 533 (rounded).

To do it from the y side, simply reverse the x's and y's.

down

geoff at spacevs dot com ¶

15 years ago

This function returns the width and height of a JPEG image from a string, allowing the dimensions of images stored in a database to be retrieved without writing them to the disk first, or using "imagecreatefromstring" which is very slow in comparison.

<?PHP
function getJPEGImageXY($data) {
        $soi = unpack('nmagic/nmarker', $data);
        if ($soi['magic'] != 0xFFD8) return false;
        $marker = $soi['marker'];
        $data   = substr($data, 4);
        $done   = false;

        while(1) {
                if (strlen($data) === 0) return false;
                switch($marker) {
                        case 0xFFC0:
                                $info = unpack('nlength/Cprecision/nY/nX', $data);
                                return array($info['X'], $info['Y']);
                                break;

                        default:
                                $info   = unpack('nlength', $data);
                                $data   = substr($data, $info['length']);
                                $info   = unpack('nmarker', $data);
                                $marker = $info['marker'];
                                $data   = substr($data, 2);
                                break;
                }
        }
}
?>

Doing this 10,000 times takes 0.43 seconds, compared with using imagecreatefromstring/imagesx/imagesy which takes around 1.52 seconds to do the same.

Do not use this instead of getimagesize when dealing with files, getimagesize is much faster coming in at 0.15 seconds.

down

cloned at clonedmadman dot com ¶

16 years ago

Well, I am making a script which will resize the image when uploaded, however, i am making a multi-uploader, so i came across with a problem: an efficient way of getting a pictures height and width and storing them in an array to resize later. This is what i came up with:

<?php
$links = array("test1.jpg", "test2.png");
$sizearray = array();
$count = count($links);
for($i = 0; $i < $count; $i++) {
    $size = getimagesize($links[$i]);
    list($width, $height) = $size;
    $sizearray[$links[$i]] = array("width" => $width, "height" => $height);
}
print_r($sizearray);
// which will print out: Array ( [test1.jpg] => Array ( [width] => 300 [height] => 400 ) [test2.png] => Array ( [width] => 680 [height] => 100 ) )
?>

down

diablx at hotmail dot com ¶

20 years ago

I'm sorry for they other scripts, but I made one mistake about the image resizing... here is a working script !
<?
    // Some configuration variables !
    $maxWidth = 90;
    $maxHeight = 90;
    $maxCols = 8;
    $webDir = "https://localhost/images/";
    $localDir = $_SERVER['DOCUMENT_ROOT']."/images/";

    $AutorisedImageType = array ("jpg", "jpeg", "gif", "png");
?>

<center>
<table border='1' cellspacing='5' cellpadding='5' style="border-collapse:collapse; border-style: dotted">
<tr>
   <?
   // Open localDir
   $dh = opendir($localDir);
   while (false !== ($filename = readdir($dh))) {
       $filesArray[] = $filename;
   }

   // Display and resize
   foreach ($filesArray as $images) {
   
       $ext = substr($images, strpos($images, ".")+1, strlen($images));
       
       if( in_array($ext, $AutorisedImageType) ) {

           list($width, $height, $type, $attr) = @getimagesize( $localDir.$images );

            $xRatio = $maxWidth / $width; 
            $yRatio = $maxHeight / $height; 
            
            if ( ($width <= $maxWidth) && ($height <= $maxHeight) ) { 
              $newWidth = $width; 
              $newHeight = $height; 
            } 
            else if (($xRatio * $height) < $maxHeight) { 
              $newHeight = ceil($xRatio * $height); 
              $newWidth = $maxWidth; 
            } 
            else { 
              $newWidth = ceil($yRatio * $width); 
              $newHeight = $maxHeight; 
            } 
           
           if($i == $maxCols) {
               echo "</tr><tr>";
               $i = 0;
           }
           echo "<td align='center' valign='middle' width='$maxWidth' height='$maxHeight'><img src='".$webDir.$images."' width='$newWidth' height='$newHeight'></td>";
           $i++;
       }
   }
?>
</tr>
</table>
</center>

down

kazuya ¶

10 years ago

i made function img_resize($path,$tmp_name,$new_name,$new_width)
this could be useful.

<?php

$new_file = img_resize("./img/", "test.jpg","copy_test.jpg",300);
echo "<IMG src = '$new_file'>";

function img_resize($path,$tmp_name,$new_name,$new_width){
    if (!file_exists($path.$filename)){
        echo "file not found!";
        exit;
    }
    if (!is_writable($path)){
        echo "error:permission denied!";
        exit;
    }
    list($width, $height) = getimagesize($path . $tmp_name);
    $new_height = abs($new_width * $height / $width); 
    $image_p = imagecreatetruecolor($new_width, $new_height);
    $image = imagecreatefromjpeg($path . $tmp_name); 
    imagecopyresampled($image_p, $image, 0, 0, 0, 0,
                        $new_width, $new_height, $width, $height); 
    imagejpeg($image_p, $path . $new_name); 
    return $path.$new_name;
}

?>

down

alexyam at live dot com ¶

12 years ago

I wanted to use getimagesize() on .SWF files stored in the database as blob data and couldn't find a simple solution, so I created my own.

I am releasing this code under the MIT license to save everyone some time:

<?php
/*
    ----------------------------------------------------------------------
    PHP Blob Data As File Stream v1.0 (C) 2012 Alex Yam <alexyam@live.com>
    This code is released under the MIT License.
    ----------------------------------------------------------------------
    [Summary]

    A simple class for PHP functions to read and write blob data as a file
    using a stream wrapper.

    Particularly useful for running getimagesize() to get the width and
    height of .SWF Flash files that are stored in the database as blob data.

    Tested on PHP 5.3.10.

    ----------------------------------------------------------------------    
    [Usage Example]

    //Include
        include('./blob_data_as_file_stream.php');

    //Register the stream wrapper
        stream_wrapper_register("BlobDataAsFileStream", "blob_data_as_file_stream");

    //Fetch a .SWF file from the Adobe website and store it into a variable.
    //Replace this with your own fetch-swf-blob-data-from-database code.
        $swf_url = 'http://www.adobe.com/swf/software/flash/about/flashAbout_info_small.swf';
        $swf_blob_data = file_get_contents($swf_url);
    
    //Store $swf_blob_data to the data stream
        blob_data_as_file_stream::$blob_data_stream = $swf_blob_data;
    
    //Run getimagesize() on the data stream
        $swf_info = getimagesize('BlobDataAsFileStream://');
        var_dump($swf_info);

    ----------------------------------------------------------------------
    [Usage Output]

    array(5) {
      [0]=>
      int(159)
      [1]=>
      int(91)
      [2]=>
      int(13)
      [3]=>
      string(23) "width="159" height="91""
      ["mime"]=>
      string(29) "application/x-shockwave-flash"
    }

*/

class blob_data_as_file_stream {

    private static $blob_data_position = 0;
    public static $blob_data_stream = '';

    public static function stream_open($path,$mode,$options,&$opened_path){
        static::$blob_data_position = 0;
        return true;
    }

    public static function stream_seek($seek_offset,$seek_whence){
        $blob_data_length = strlen(static::$blob_data_stream);
        switch ($seek_whence) {
            case SEEK_SET:
                $new_blob_data_position = $seek_offset;
                break;
            case SEEK_CUR:
                $new_blob_data_position = static::$blob_data_position+$seek_offset;
                break;
            case SEEK_END:
                $new_blob_data_position = $blob_data_length+$seek_offset;
                break;
            default:
                return false;
        }
        if (($new_blob_data_position >= 0) AND ($new_blob_data_position <= $blob_data_length)){
            static::$blob_data_position = $new_blob_data_position;
            return true;
        }else{
            return false;
        }
    }

    public static function stream_tell(){
        return static::$blob_data_position;
    }

    public static function stream_read($read_buffer_size){
        $read_data = substr(static::$blob_data_stream,static::$blob_data_position,$read_buffer_size);
        static::$blob_data_position += strlen($read_data);
        return $read_data;
    }

    public static function stream_write($write_data){
        $write_data_length=strlen($write_data);
        static::$blob_data_stream = substr(static::$blob_data_stream,0,static::$blob_data_position).
            $write_data.substr(static::$blob_data_stream,static::$blob_data_position+=$write_data_length);
        return $write_data_length;
    }

    public static function stream_eof(){
        return static::$blob_data_position >= strlen(static::$blob_data_stream);
    }

}
?>

down

ajreading at classixshop dot com ¶

19 years ago

A simple piece of code i wrote to proportionally resize an image to a max height and width then display it

<?php
// Max height and width
$max_width = 100;
$max_height = 100;

// Path to your jpeg

$upfile '/path/to/file.jpg';
    Header("Content-type: image/jpeg");
    
    $size = GetImageSize($upfile); // Read the size
          $width = $size[0];
          $height = $size[1];
          
          // Proportionally resize the image to the
          // max sizes specified above
          
          $x_ratio = $max_width / $width;
          $y_ratio = $max_height / $height;

          if( ($width <= $max_width) && ($height <= $max_height) )
          {
               $tn_width = $width;
               $tn_height = $height;
          }
          elseif (($x_ratio * $height) < $max_height)
          {
               $tn_height = ceil($x_ratio * $height);
               $tn_width = $max_width;
          }
          else
          {
               $tn_width = ceil($y_ratio * $width);
               $tn_height = $max_height;
          }
     // Increase memory limit to support larger files
     
     ini_set('memory_limit', '32M');
     
     // Create the new image!
     $src = ImageCreateFromJpeg($upfile);
     $dst = ImageCreateTrueColor($tn_width, $tn_height);
     ImageCopyResized($dst, $src, 0, 0, 0, 0, $tn_width, $tn_height, $width, $height);
     ImageJpeg($dst);
// Destroy the images
ImageDestroy($src);
ImageDestroy($dst);
?>

down

freecorvette at gmail dot com ¶

7 years ago

For some images, using getimagesize() without the second parameter will return the correct info, but when you add the second parameter it will return false. This is most likely a bug (and it has been reported as such), but meanwhile, if you encounter this problem, a workaround is to use exif_read_data().

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Jesus Zamora ¶

13 years ago

Returns a array with 4 elements.
The 0 index is the width of the image in pixels.
The 1 index is the height of the image in pixels.
The 2 index is a flag for the image type:

1 = GIF, 2 = JPG, 3 = PNG, 4 = SWF, 5 = PSD, 6 = BMP, 7 = TIFF(orden de bytes intel), 8 = TIFF(orden de bytes motorola), 9 = JPC, 10 = JP2, 11 = JPX, 12 = JB2, 13 = SWC, 14 = IFF, 15 = WBMP, 16 = XBM. 

The 3 index contains ' height="yyy" width="xxx" '

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anonymous ¶

15 years ago

Note that if you specify a remote file (via a URL) to check the size of, PHP will first download the remote file to your server.

If you're using this function to check the size of user provided image links, this could constitute a security risk.  A malicious user could potentially link to a very large image file and cause PHP to download it.  I do not know what, if any, file size limits are in place for the download.  But suppose the user provided a link to an image that was several gigabytes in size?

It would be nice if there were a way to limit the size of the download performed by this function.  Hopefully there is already a default with some sensible limits.

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mail at soylentgreens dot com ¶

19 years ago

How about this for cropping images...

<?php

$imgfile = "img.jpg";
$cropStartX = 300;
$cropStartY = 250;
$cropW   = 200;
$cropH   = 200;

// Create two images
$origimg = imagecreatefromjpeg($imgfile);
$cropimg = imagecreatetruecolor($cropW,$cropH);

// Get the original size
list($width, $height) = getimagesize($imgfile);

// Crop
imagecopyresized($cropimg, $origimg, 0, 0, $cropStartX, $cropStartY, $width, $height, $width, $height);

// TODO: write code to save new image
// or, just display it like this:
header("Content-type: image/jpeg");
imagejpeg($cropimg);

// destroy the images
imagedestroy($cropimg);
imagedestroy($origimg);

?>

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-1

Coodiss at w3bbix dot net ¶

19 years ago

Heres a easy way to scale images to the <td> that they are in
*this is broken up so anyone can understand it :)

<?
$imageinfo = getimagesize("images/picture.jpg");
          
$ix=$imageinfo[0];
$iy=$imageinfo[1];

$widthscale = $ix/175;  //<TD> WIDTH
$heightscale = $iy/175; //<TD> HEIGHT

if($widthscale < 1)
$nwidth = $ix*$widthscale;
else
$nwidth = $ix/$widthscale;

if($heightscale < 1)
$nheight = $iy*$heightscale;
else
$nheight = $iy/$heightscale;

?>

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-1

user at example dot net ¶

16 years ago

When validating images, allways check both, image type *AND* file extension!

Because most image types allow sections for comments or other irrelevant data. Those section can be used to infiltrate php code onto the server. If these files are stored as sent by the client, files with a ".php" extension can be executed and do tremendous harm.

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-1

pfarthing at hotmail dot com ¶

16 years ago

Correction: to find $y2 it should be...

// set y side to a proportional size
$y2 = $m * $x_max; // not $x1

Thanks Norbert =)

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