Am I confused about what browser history is or what? Unless you open a static image in a new tab to look at it or you download it (as opposed to simply looking at it on the page it's on), then how on earth would its URL show up in browser history, which by definition tracks user-visited webpages (i.e. top-level links) and not every single URL the browser makes a request to?

Sure, info about non-top-level links is extractable from e.g. request caches, but that's a different thing from the browser history SQLite DB.

It sounds like you're mostly just confused about how web pages work.

Here is the URL of an image as it appears in your browser history: https://cheezburger.com/10357071872/if-i-fits-i-sits

See if you can figure out what image I was looking at.

That's not the URL of a static image, that's the URL of a web page that happens to have a static image as the only content of worth in it and puts the description of said image in the URL.

Calling it the URL of an image seems to me like quite a bit of confusion about how web pages work.

That all depends. Is "1835 73rd Ave NE" Bill Gates' address, or would it be more natural to call it the address of his house?