I noticed that the magnifier button no longer activates the magnifier. Instead, it opens the image in a new browser tab. I don’t think this is the expected behavior.
This the expected behavior on your phone - the full res image opens in a new tab so one can zoom using the pinch-zoom gesture we all know.
On Firefox on desktop, however, this should not be happening. What FF version are you running? I can’t reproduce this issue on my FF, so I’ll try yours.
Oh yes, that makes perfect sense on the phone! I should have thought of that and remembered this difference in behavior. It actually made me think the issue was more general than it really is, which sent me down the wrong path…
On my PC, I’m using Firefox 156.0.1, but following your answer, I did a few more tests and realized that it’s not actually related to the browser, but to my desktop environment.
I’m on Linux and using the COSMIC desktop environment (a relatively new and, I guess, rather niche DE). With this DE, I can reproduce the behavior I described in both Firefox and Chromium. However, if I switch to a KDE session, it works as expected in both browsers.
I realize now that this is probably specific to this Cosmic environment, but I’m surprised that it could have any influence on such a specific action in a web browser! Anyway, I’m not sure it’s really worth investigating further for such a specific (and minor) issue.