Hellooo!
I've almost completely rewritten Shrunked, it should now work on any website - including Facebook and GMail which previously had known issues.
I'm currently testing and polishing it. You can get a beta of the new version from https://s19367.gridserver.com/software/addons/shrunked@darktrojan.net.xpi. It's missing a few icons and things and needs a bit more work, but so far it has been pretty good. Try it out.