.png images and UAC

IE7 does not display .png images. All other
images display correctly. The .png images appear as red-x's on any page that
has them.

I did some testing and found that if I log on as another user (IE: guest),
then .png images display in IE7. Also, if I run IE as Administrator, .png's
display. Furthermore, if I turn of UAC, .png's display correctly.

Only when I am logged on to my account, with UAC enabled, the .png's are
blocked from IE. Everything else is working fine. I have tried re-setting
IE back to factory settings, disabling all add-ins, turning off protected
mode and phishing filters. My Multimedia settings in Advanced Options are
correct. My registry has the proper associated entries for .png.

Lots of articles point to re-registering the pngfilt.dll file, but it is
registered properly with the latest version.

I believe this is a direct result of an issue with UAC. I still want to
keep UAC enabled, but I would like to correct this problem without running IE
as Admin all the time.

Any suggestions? Thanks in advance.

Jim