Rated 4 out of 5 stars
FYI, seems to be working fine with FF4.
One little problem I ran into: when an image has no real file name defined in the source code (for instance /index.php?view=image&format=raw&type=img&id=48010&option=com_joomgallery&Itemid=202), the add-on doesn't seem to be able to get the correct file name, and opens a "save as" dialog box with the name "unknown.ext" pre-entered. What puzzles me is that Firefox's regular "save image as" action does get the correct file name (and extension). So it would be nice (if possible) if the add-on used the same mechanism as Firefox to get the correct file name in those situations.