I can't quite believe I'm not just being careless. Doing it again. Add photo. Preview, click photo, close it. Right, it opens in the same tab, says attachment, has a back button. But I don't notice the back button, close the tab. Can restore the tab from history, then click the back button. But once the thread is started, I think it always opens a new tab.
I've already tested that advanced edit opens a new tab if you click a picture in preview. What about reply? I was right - reply also opens a new tab - it's only for a new thread that clicking the photo opens it in the same tab, and I'm pretty sure that's different from what it used to be, because I used to do that a lot.
