Well if you use and animated spray without the actual animation, then I think it should make it come to the top again. cause it has to refresh it. so I guess with the refresh, the newest picture comes on top.
so if you have 1 picture, make it animated with the same picture (so you'd get an animation with 2 of the same pictures [meaning no movement]) and then with the refresh it should come on top.
PS: it's just a theory I just thought of out of the blue. don't start yelling if it's BS