using v1.3 Rated 4 out of 5 stars

good, but needs some polishing:
-- after you resize an image, the cursor changes to Hand, regardless if the image was a link or just plain image. This is confusing...
-- why not use Shift to toggle the Free X-Y scaling on and off?
-- would be nice to have a command (e.g. Alt+RMB) for scaling an image directly to the size of the window (like 'fullscreen' in one shot)
And THANK YOU for No-Restart !

This review is for a previous version of the add-on (1.2.rev653.1-signed.1-signed). 

1. This was an experimental idea hence 1.3 being a separate link.
2. I cannot hide the context-menu that popups when you right click an image if the user is holding Shift, so I decided to go with ALT instead.
3. Ctrl+MiddleMouseButton, though that's a glitchy hidden feature!

No problem :)

I have uploaded v1.3 to Mozilla which adds the ALT feature.