Transparency, Resizing Width and Height, Clipping Width and Height, Making one image overlap another one.
There are the "tricks" I know, and with them, you can make some graphical effects which are pretty cool. (I simulated a rotating tree which actually looked 3d, using nothing but these effects, but I managed to mess up, so I can't show you right now >_>).
Simply, what I am asking is, what else things can you use to manipulate images, or at least how the viewer sees the image? Do you have any other tricks you can share?
Of course, I know there are lots of other things, such as FlipImage(), but the things I'm looking for must be cross browser for at least the main browsers.