This script creates transparency for a unspecific RBG color for an already created PNG image. It also includes script of overlay text that does not get ruined in the process.
<?php
header("Content-type: image/png");
$image = imagecreatetruecolor(250, 250);
$string = $_GET['text'];
$im = imagecreatefrompng("dynIcon.png");
$img = imagecreatetruecolor(16,16);
$orange = imagecolorallocate($im, 220, 210, 60);
$bg_color = imagecolorat($im,1,1);
$px = (imagesx($im) - 3 * strlen($string)) / 2;
imagecolortransparent($im, $bg_color);
imagestring($im, 3, $px, 5, $string, $orange);
imagepng($im);
imagedestroy($im);
?>
Use $bg_color = imagecolorat($im,1,1); for instance, if you made the transparent color in photoshop by clearing out all the color leaving you with the checkered background showing you it's empty.
