How to crop one layer without cropping all when creating a frame animation

OK, I think I misunderstood your post — it 'is' 3am here.  I read crop as remove, but I think you meant reduce canvas size.  If that's the case, then the crop tool is not what you need to use if you only want to affect one frame.  In this case you can use a layer mask on the particular layer associated with the frame you want to crop, so longs as that layer is only used once.

Is that making sense?  Describe some more, and maybe use screen shots if it helps describe what you wish to achieve.

Hi Laura

What exactly are you doing when you say you crop one photo?  What you should be doing is selecting the frame you want to remove in the timeline, and delete that.  There's no need to delete any layers.