tried 1.3, but the reason of the bug I experienced was elsewhere Rated 5 out of 5 stars

I found out why the context menu appears for me. The thing is that I don't have checkbox "Disable context menu" checked at "Menu-Options-Content-Enable JavaScript-Advanced".
I hate when some sites disable context menu via javascript, but I want your extension to not cause opening context menu for me. Is it a fixable issue?

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

awesome! Rated 5 out of 5 stars

Eliot, thank you a lot for changing the trigger button to RMB.
However, RMB still opens the context menu upon releasing the button.
I also found that this consequence doesn't trigger context menu: RMB down, LMB down, LMB up, RMB up.
(where down = push and hold the button, and up = release it).

Since you didn't give up development (phew!), here is another bug report:
After zooming a picture in/out, sometimes it is needed to set it's initial size. In 'Image Zoom' extension this combo served for good: click MMB while holding RMB.
In your extension - it just sends a middle click to the image, so if the image is an URL - you'll get a new tab opened with that URL. The same for LMB (while RMB is being held).
I think you could use "hit MMB while RMB is held" to resize the image to it's initial state. And if it's already in it's initial state and the user again hits MMB while RMB is held - you could maximize the image to fit the screen.

Thank you for improving your extension, the latest version now replaced me the old, outdated, buggy, leaky, non-restartless Image Zoom.

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

I can't reproduce those issues

This is weird, for me the RMB doesn't open the context menu unless I did not move the mouse.

You can restore images by just clicking with RMB if the image was resized before.

Not sure what you mean with the MMB, are you talking about maximizing the image? That's not a recommended feature, I just put it there for exceptional cases.

[Edit]: You can try out v1.3 from my website

A good resurection of Image Zoom extension Rated 5 out of 5 stars

It is awesome that you've created this extension and especially that it is restartless. But could you please provide some settings?
Over the years of using Image Zoom extension - I really got used to holding Right Mouse Button + scrolling down/up to increase/decrease the image.
Left Mouse Button is not a wise choice: it may automatically do some actions on the page (even if you didn't release the button) and that happens way more often than sites use the same kind of handler for Right Mouse Button click.

Actually, I'm not happy at all that Image Zoom is dead long ago (it's development stopped, but it still works), as it is not restartless and works only when you have a mouse with a wheel (I got netbook with touchpad, and of course it doesn't work there), but I'm also not really happy with your extension as it breaks drag-n-drop completely, so I insistently suggest you either to add settings or change the LMB to RMB (or maybe MMB).

This review is for a previous version of the add-on (1.1.rev361.1-signed.1-signed). 

Thanks :)

Version 1.2 has been uploaded, and is yet to be reviewed by Mozilla but you can try it out if you can't wait. The new version fixes and improves several things though the most important change is that LMB has been swapped with RMB.