Rated 5 out of 5 stars

It works just fine on Firefox 45 (and 44 and 43 and those before) and it is multiplatform (I am on SunOS that is Openindiana hipster/illumos)
allows to rotate, zoom, just what would one need viewing images.
I would suggest to add option of setting default settings for fit Zoom width, but since I can enable right click>FitWidth ,it could be said it is good enough and well suited. Support the author! :)