A few dozen thousand people certainly feel it does, I just can't promise it works on every website and every image.

That's how it has always worked, perhaps your website changed the way its image links work. This addon is an image downloader, not a thumbnail resolver. It has no idea if an image is a thumbnail link or not, it can't factually decide such things. Please use a different addon for such uses, and please update your review according to the addon's performance compared to its listed functions rather than that it lacks a tangential feature you wish it had.

PS: for many thumbnail links you don't need an addon, just alt-click the link to download whatever it points at. This may often be a webpage instead of an image though, and firefox may still need you to enable alt-clicking in its settings first.

Thanks for the simple and honest summary. For fairness' sake, just know that firefox specifically does not even implement the download renaming API. Firefox addons could not add a missing extension even if the developer really wanted to.

Edit/reply: not in the way you think. Those addons determine their own filename from a bunch of guesswork. I consider that an anti-feature and want to leave the initial naming to the browser.

Websites will sometimes have a design that stops this addon from working. It is ultimately something of a hack, I try to make it work as well as I can but the code can only work around so many obstacles. It'll never work everywhere and we're at a point where there isn't much potential improvement left for the detection mechanism. Sorry 'bout that.

Glad you like it, thanks. :) As for the toolbar, this depends on your browser I think. I use vivaldi and edge and get a button for every addon. I might be able to force it but I'll have to look into it.

Certainly a fair remark, though just for clarity I'd like to point out this is simply the nature of twitter's image hosting/linking, not a shortcoming in the addon. File extensions are a mere semantic convention and mostly only relevant in filesystems for human users. In HTTP-hosted resources, they're a mere courtesy a server/URL can decide not to offer. Other websites will similarly not include a file extension, and there's little an addon or browser can do about it (especially in firefox, which still doesn't implement filename manipulation for addons).

I just checked again, and the file extension could be derived from other data in twitter's URLs, but it would require both the missing renaming implementation in firefox as well as special handling code in my addon just for twitter. The latter I indeed choose not to implement, even for the chrome-based browsers that would support it. :)