(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)
imagecopymerge — Copy and merge part of an image
$dst_image,$src_image,$dst_x,$dst_y,$src_x,$src_y,$src_width,$src_height,$pct
   Copy a part of src_image onto
   dst_image starting at the x,y coordinates
   src_x, src_y  with
   a width of src_width and a height of
   src_height.  The portion defined will be copied
   onto the x,y coordinates, dst_x and
   dst_y.
  
dst_imageDestination image resource.
src_imageSource image resource.
dst_xx-coordinate of destination point.
dst_yy-coordinate of destination point.
src_xx-coordinate of source point.
src_yy-coordinate of source point.
src_widthSource width.
src_heightSource height.
pct
       The two images will be merged according to pct
       which can range from 0 to 100.  When pct = 0,
       no action is taken, when 100 this function behaves identically
       to imagecopy() for pallete images, except for
       ignoring alpha components, while it implements alpha transparency
       for true colour images.
      
| Version | Description | 
|---|---|
| 8.0.0 | dst_imageandsrc_imageexpect
       GdImage instances now; previously, resources
       were expected. | 
Example #1 Merging two copies of the PHP.net logo with 75% transparency
<?php
// Create image instances
$dest = imagecreatefromgif('php.gif');
$src = imagecreatefromgif('php.gif');
// Copy and merge
imagecopymerge($dest, $src, 10, 10, 0, 0, 100, 47, 75);
// Output and free from memory
header('Content-Type: image/gif');
imagegif($dest);
imagedestroy($dest);
imagedestroy($src);
?>