[PHP] image question again

[Karl DeSaulniers]

When I have an imagecreatetruecolor and I create another one and use  
imagecopymerge, how do I keep the backgrounds transparent even if say  
the width of the top image is smaller than the back image?
I keep getting a black background where the top image does not cover  
the back. It sets the transparency to the rest of the top image as  
long as it is covering the bottom one. I think it has to do with the  
imagealphablending.
Any ideas?
TIA

Karl DeSaulniers
Design Drumm
http://designdrumm.com