This is my biggest headache and nothing has improved in my months I've been using 7.1 to build my site. It's difficult enough to arrange my images without buggy glitches making it take 50 times longer than it should. The only way I make any progress is by saving my work after every few moves, then trying again and hoping it will allow at least one image to stay where I move it to. Arranging photos is such a fundamental need, I can't believe this isn't fixed yet.