EDIT: it would be good if the blocking would work not only for certain sites (also where it sometimes does not), but also for certain file types (like gif, webm).
Set the pop up size to 50% otherwise it won't work. Offers invert black list. Images are centered and large enough. Works even on Xenforo galleries with broken lightbox, nice workaround, you can still right click and save "through" the hovered image. Thank you to the developer, don't change anything, except if you want to look at Hover Zoom! and implement all their features (action keys etc). But this add on right here has better file type recognition and thus wider functionality even with recognizing and filtering .webm(followed by numbers).

Allow videos to have sound?

Some ins and outs but this add-on works fantastically for me. Does exactly what it intends to do. Doesn't work with some sites, but that's because of the sites, not because of the extension. Sites where it doesn't work can be whitelisted. Some images are not the size you expect, also not the add-on's fault. What more could you ask?

Works better than the other one, more customizable too

a good replacement for the old amazing "thumbnail zoom plus"

Works great on tumblr links, example : geenstijl.nl/mapje/vrijmibo/
can you make an addon which switch tabs when hoover over them? (like in Tabmixplus..)