I know how to do that too.
you don't la
yer it. you have one image open and you save it (for that, Zenirix or soemthing). Then you rotate it slightly and save it again. This time, add a 1 on the end of the name. Then rotate it slightly more and repeat this action.
When your finished, open up the first one. You make new layers, a bunch at a time. Then you select the first clean new la
yer. You open up the second slightly turned image. Open it up so it IS NOT IN THE NEW la
yer YET! Open it up as it's own. Press apple and A so you select the whole thing and copy it. Return to the one that has the layers on it and paste the new image in the new la
yer.
When you finish doing that with all the layers, go to window and pres animation. A bar will appear with frames on it. There is also a tab that makes new frames (same little box as you click to make a new la
yer). One the first frame you use the first la
yer. To do this, you make all the other layers not visable. Then you move to the second frame la
yer in the animation and you make only the second la
yer in this visable and so on and so on until your finished.
If you need further help, I can try to explain (it's hard) or I can direct you to the you tube video I used.