png / gif background color FIX
Transparent background now working, thanks Jimmy Wu! Here's the fix:
1) Upload the png / gif images WITHOUT TRANSPARENT BACKGROUND using the powerstore admin upload.
2) Go back and knockout the background color in Photoshop/Fireworks and overwrite the original png / gif file (from step 1).
3) Manually upload this file to the /Images/Upload/ directory (bypass the PS upload).
It seems that when you use the Powerstore upload in the admin area, something adds the black background. I'm sure WA will find a cure for this extra step.