This script I prefer:

http://userscripts.org/scripts/show/56738

I used to depend on Customize Google the Firefox addon, but as that is no longer maintained the google image rewriting functionality no longer works.

After trying all the Google Image Greasemonkey scripts I could find, I came across this gem that works just as I had wanted.

Clicking the image thumbnail goes to the image directly, and clicking the link below it takes it to the source page directly, no unnecessary Google image frame page.

If you want to be able to see the full image version of google image search, without the clutter they usually add, this is your script.

Works flawlessly and it is fast. You get to choose the quality and size as usual from google menu, then you just get the real link.

Great GM Userscript.

The google image direct link script is one of my must-haves. I've been through them all as google gets to eventually disable. This script facilitates the best iteration of direct link imagery I've yet seen. I only hope that google keeps its grubby, greedy claws off of it!