This issue has plagued me for years. I’m pretty sure the issue came about from messing with color profiles on my Mac. I switch between web and print graphic work a lot, so somewhere along the way I must have checked the wrong box, thus leading to color shifts when saving PNGs using Photoshop CS2′s Save for Web.

The symptom is commonly as follows. Using CSS, you have set an area to have a solid background color, say #333333. Using Photoshop, you’ve created a graphic whose background color is #333333 to match your area’s background. But, when the PNG is rendered in a browser, the backgrounds don’t match. In my case, using Apple’s Digital Color Meter shows that the background color of the PNG is actually #434343 in Firefox.

I finally found an easy fix on the Polar Bear Lamps blog. This amazing post describes in easy detail how to open a PNG after saving, strip it of meta data, and re-save it.  Apparently, the embedded Gamma meta data from Photoshop causes the shift.  Delete that meta data, and the shift disappears.

The post comments also reference tools for drag and drop use. I downloaded GammaSlamma 1.1, and its working nicely.

Thanks so much to Polar Bear Lamps for quelling that buzzing in the back of my mind.