If you’re having the same problem I did, where when you upload an image to WordPress it does not let you change it from the original uploaded size, then simply do the following (on Gentoo):
For those of you on other distros, try doing the same thing with your package manager, or just install the GD libraries from scratch (you can find them here: http://www.libgd.org)
Of course, this won’t be effective without recompiling PHP to use GD, so again, on Gentoo:
And again, on other distros, you’ll have to do some digging yourself to either A) use your package manager to recompile PHP or B) recompile it by hand.
Once that’s all said and done, you should be able to click the buttons to select a small, medium, or large image as well as the original one. Nifty? I think so…