Rated 5 out of 5 stars
This add-on certainly is clutter-free (because it allows you to zoom the image in its own page after you click "view image" in the context menu. It provides great functionality, but I recommend reading the user guide. Reach the guide by pressing F1 with the options panel open or by selecting (in the same panel) "Enable Context Menu [Items]" then selecting the user guide option from the context menu while viewing an image.
I had trouble at first getting the add-on to work properly, because the hotkey to zoom in/out conflicted with Firefox's page zoom in/out hotkey (CTRL+mousewheel up/down). It took me a while to figure out what to do to fix the problem, so to save you the trouble (if the same problem occurs for you) here's what I did:In URL bar type "about:config" (without quotes),Click "I'll be carefull, I promise!,"Go to "mousewheel.with_control.action,"Change "3" to "2."
I considered giving this add-on four stars because of the hotkey issue, but I am still giving it five because it is an image zoom add-on that is above the others I've tried.