I think my problem has no solution, but I thought I'd ask again in case someone has found the answer since the last message that said there was no solution.
I HATE the shadows that Leopard puts around windows. Not so much that I'm generally against eye candy (sigh), but that they prevent me from doing an important task accurately. If Apple had a plist pref or something I could change... but no one seems to have found it. Even ShadowKiller, which worked in Tiger, has thrown up its hands and hasn't been updated to work in Leopard.
The problem is that I often have two windows open, each with a slightly different version of the same photo. I arrange them to overlap, and thus put similar parts of the photos immediately adjacent to each other. Then I want to judge which one I like better.
I CAN'T DO THIS IF THE SHADOW DARKENS ONE OF THEM AND NOT THE OTHER!!! What was Apple thinking???? That eye candy was more important than color/brightness professionalism?? This is super-frustrating because THERE IS NO WORKAROUND.
Sure, only a percentage of Apple users have a PRACTICAL reason to turn off these shadows, but those of us who do, really REALLY need to.