You can make overlays on many apps. Overlays are images without backgrounds. (PNG transparent images.) I use an app called Eraser that can be downloaded on a mobile device, and has a tool that helps you get ridd of the background.
This helps in animating overlays:
I will use one of the ones I have made as an example:
The image example:
The overlays I used to make it:
ARM 1 (Using animation: talk_handsonhips, with arms rotated.)
ARM2 (ARM1 reversed)
UPPER BODY (yawn_bored)
SKIN OF CHARACTERS COLOUR (This will cover the mouth, so you can have the mouth overlay move.)
LIP (Animation: eyeroll)
The character also has wound overlays aswell.
Does this help?
–Invisible Waffle