if you want to animate edges, try Roughen edges effect and animate the evolution parameter. it will create a shaking of the contour. you will need to refine some parameters.
if you want something more specific, you should show us your artwork and illustrate (by reference or other means) what exactly you wish to accomplish.
i just want to shake a little the edge/contour of my transparent psd to make a small breeze hair effect.
i test that
Make a short breeze like motion with the puppet tool. Then duplicate the key frames a bunch of time to make the animation move continuously. You can also loop the comp, once you establish the keyframes. Here's a short video on how to loop comps After Effects Tutorial | After Effects | Looping Compositions - YouTube