I use the custome colour settings, mainly because I hated the Renderosity colour scheme when I signed up, but I still use and much prefer and black background for the galleries. Dark backgrounds do display images better. Hell, if I had my choice, I'd force people to turn off all the lights in the room when viewing my images too!

So, my question is this - If DARK images benefit from a darker background then do LIGHTER (or HAPPIER, whichever) images benefit from a lighter background? And, if this is the case - what is the happy medium for all of the images?

It would take a little more work, but why not add another set of check boxes to the image upload sceen. You have a check box for violence, nudity, comments and ratings, why not add one for "display on black background" and "display on white background"?