The image search speed is very fast. By clicking +Preferences, you can set the image search options, including safe filtering, size, color, and file formats, etc. For the search results, you can bookmark them at the bottom of the page, or click to zoom in and out, open separately for viewing, etc. Moreover, it will also display the image's size attributes, etc. Especially, it supports free dragging, which is a great feature.
This site currently supports Firefox 1.5+.
Address: http://elzr.com/imagery