I ended up just treating it like a transparent gif and selecting a color to be transparent, and it works great, but I'm getting jagged edges, and I would love the soft shadows I can get with an alpha png.
Here's my current php script:
<? header ("Content-type: image/png"); $background = imagecreatefrompng($_POST['bkg']); $overlay = imagecreatefrompng($_POST['char']); imagecolortransparent($overlay,imagecolorat($overlay,0,0)); $insert_x = imagesx($overlay); $insert_y = imagesy($overlay); imagecopymerge($background,$overlay,0,0,0,0,$insert_x,$insert_y,100); imagepng($background); ?>
I've seen transparency functions within gd that seem to allow use of the alpha of the png, but I can't get them to work with imagecopymerge. I'm sure it's me doing something wrong, but I don't know what. I hope my explanation above is clear.
Anyone here have an idea of how I can accomplish this.