Problem: Firefox consistently refuses to load images on certain specific websites, which may or may not be image-heavy. Examples may include Aliexpress or Google image search.
Firefox may also refuse to show map images on sites with map functionality, such as Kijiji / Craigslist and Samsung SmartThings Find, and news stories from the BBC, Propublica and others may be missing their images. Images will just not show, or show placeholders; maps will show as "Sorry, we have no imagery here", or similar.
Other websites are consistently fine, and Chrome does not have any problems with the "bad" sites. The usual fixes, such as clearing cache / cookies, don't work, limiting the problem to specific sites only.
Fix: Firefox may be set to not load "webp" images, which are getting more and more popular. The solution is here.
I lived with this for almost 2 years and was beginning to think I'd have to switch to Chrome to get around it. (I'm not a Firefox devotee, but I also don't like changing things around.) I can't figure out why the webp loading setting was not enabled by default, or if it was, how it got switched off.