If you've looked at Google today you may have noticed that they're offering a Windows program as a download; Picasa, which seems to be a rather nice image viewing and sharing program. I've tried it on my PC, and it works fairly well; doesn't catalogue .gif files unless you tell it to, and insists on sorting things by date before directory, which is a bit of a nuisance, but if you can work with that it's okay.
One interesting but potentially embarassing thing it can do is show every picture that's still in your browser cache, which might be handy if you look at a picture, forget to bookmark it, then want to go back to it. Rather useful provided your cache isn't full of porn etc.; for some reason mine currently seems to be full of pictures of Sabrina (see yesterday's entry) which is harmless enough, but some people might want to be a little more careful.
Also on the subject of images, here are some more for Twisting the Hellmouth's user interface
( pretty pictures )