Rated 5 out of 5 stars

Is it possible to choose on which screen the fotos pop up? Like if you have one in landscape mode, and the other one in portrait mode (1920x1080 and 1080x1920), the fotos in landscape format pop up on the landscape screen, and the portrait format fotos pop up on the portrait screen?

This review is for a previous version of the add-on (2.7.1-signed). 

Rated 5 out of 5 stars

Great addon. I once switched to Chrome, because of the HoverZoom addon and I didn't find one for Firefox, until I found this little gem. But: could you add a function for links to Flickr? I regularly browse Reddit, but many people there post pictures from Flickr, but this addon doesn't work with that site. I must be possible, because RedditEnhancementSuite does it. Maybe also for Imgur albums? Something like on hover the first picture is opened and by pushing the arrow-keys the pictures switch to the next. That would be awesome. You anyway get 5 stars from me :)
Edit: There is also a bug, that doesn't allow to show a picture when scrolling down without moving the mouse.

This review is for a previous version of the add-on (2.3.1-signed). 

Thanks for your review. Flickr.com links and imgur albums are already supported in the latest beta https://addons.mozilla.org/en-US/firefox/addon/thumbnail-zoom-plus/versions/ . This is planned for the official 4.2 release.

The issue about images not popping up when you scroll is actually a feature, not a bug. If you want those pop-ups, go to Thumbnail Zoom Plus preferences and turn on "Scrolling triggers pop-ups".