Use a brush to create a thick line.To create a 3x3 red brush:<?php$brush_size = 3;$brush = imagecreatetruecolor($brush_size,$brush_size);$brush_color = imagecolorallocate($brush,255,0,0);imagefill($brush,0,0,$brush_color);imagesetbrush($im,$brush);?>Then use imageline() or imagepolygon() with IMG_COLOR_BRUSHED as the color.To stop using the brush, destroy it:<?php imagedestroy($brush); ?>The brush can also be created from an existing image.