ETA: Speaking of mistakes, I had to go to another computer to figure out what was going on with 1145 and 1152 - both images were on consolegames.ro, which doesn’t allow hotlinking. I’m still surprised that the message to that effect didn’t show up when I switched browsers but not computers, but now I know to avoid that site, anyway.
I think the issue comes from the image still being in your browser’s cache. Until you quit & restart or manually flush your browser’s cache, the direct image link will still work even if the website disallows hotlinking. Unfortunately that means there’s no easy way to know if your image will actually work, until everyone else starts complaining about it. :o
ETA: Well, that’s the thing: I was opening them up in a different browser, just to deal with that issue. Or so I thought. Maybe it’s a bad assumption, but I would have figured that Firefox and Chrome would each have its own separate browser cache.