Works, but not quite the way I'd like. When you turn it on, you can only see alt text by hovering over an image (so you can't see the alt text of all images on a page). And when an image doesn't have alt text, it shows the filename as the alt text, which is confusing. So if those could be changed, I would be happy to give this 5 stars.

The add-on works well! It's simple and easy to use. However, I would greatly appreciate having the ability to have the feature turned off by default and turn it on when needed. This is because I do not need the pop-up on every image of every URL and it becomes annoying quite quickly. :)

Does what it says :) (though I use it for checking screen reader accessibility)