Not sure if the random photos is here to stay but that's what I've found so far.
Not the problem. I am looking in my photo gallery. Other members' pics are displayed in place of the ones I attached to the posts.
In one case the thumbnail pic does not even match the enlarged image. Both belong to somebody else.
The trouble with common sense is it is no longer common
That's been happening since I've signed up. It happens when somebody uploads a photo with the same filename as yours already in the gallery. Just upload it again and now yours appears in their gallery.
Or forget the mtbr gallery entirely and use an off-site photo website.