[Image-SIG] Please help !

[Shi, Xuan]

To whom it may concern,

I am a GIS Analyst/Programmer at West Virginia GIS Technical Center. I am
glad to know that someone had fixed transparency handling before for GIFs,
XPMs and PNGs, according to the following messge thread that I found at:

http://mail.python.org/pipermail/image-sig/1996-December/000177.html 

Please help me to figure out how to make such composite images. Currently, I
have one png image with transparent background and want to overlay it on top
of another image (jpeg). However, what I want to do is to make only
transparent color as transparent on the composite image while keep all other
non-transparent colors unchanged. In my approach, all colors in the png file
are transparent. Any suggestions will be greatly appreciated. I am looking
forward to hearing from you.

Best wishes, 

Sam