Mata,
AE will give you a bit better scaling than FCP, but you can do a lot of compositing in FCP, if you know the ropes. You should optimize your stills in Photoshop, 72 dpi at no bigger than say twice your project frame size. This is usually enough for most moves and zooms.
If this doesn’t smooth your moves as well as AE, then do it in AE and render in Animation+ with a straight alpha channel and you’ll be good to go. If you don’t need an alpha channel then skip the last step
Have a wonderful day.