/**
 * PNG ALPHA CHANNEL SUPPORT for imagecopymerge();
 * This is a function like imagecopymerge but it handle alpha channel well!!!
 **/
function imagecopymerge_alpha($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h, $pct){
    $opacity=$pct;
    // getting the watermark width
    $w = imagesx($src_im);
    // getting the watermark height
    $h = imagesy($src_im);
    
    // creating a cut resource
    $cut = imagecreatetruecolor($src_w, $src_h);
    // copying that section of the background to the cut
    imagecopy($cut, $dst_im, 0, 0, $dst_x, $dst_y, $src_w, $src_h);
    // inverting the opacity
    $opacity = $opacity;
    
    // placing the watermark now
    imagecopy($cut, $src_im, 0, 0, $src_x, $src_y, $src_w, $src_h);
    imagecopymerge($dst_im, $cut, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h, $opacity);