Sorry for the late reply. I might be extrapolating a bit too much from your request, but are you looking for a way to automatically reverse image search the image, and find larger versions?

If so, that's actually not what this addon currently does. It doesn't replace using a reverse image search engine, but rather complements it, because image search engines will often not provide the largest version that a site will offer.

This addon works by using APIs and regex rules specific to each of the sites it supports to find the largest publicly available version of the image that the site offers. For example, let's say that a website has the following images:

example.com/image_small.jpg
example.com/image_large.jpg

If this addon had a rule for that site, it would replace image_small.jpg with image_large.jpg, based entirely on the URL of the image (replacing _small with _large).

I'm not against adding support for reverse image search engines in a future version, but I'm not sure when I'll have time to get to that. If someone else would like to contribute this in the meantime though, I would be more than happy to accept a PR! :)