Hello!
@amserra did you ever find a simple solution to what you are trying to do?
I too would like “pixel-perfect” collision detection for my sprites and am baffled as to why the physics body is built from the bounding box around the image rather than only the non-transparent pixels of the image/animation…
I have opened a GitHub issue here about this to see if we could maybe add this functionality to the framework as I’m sure anyone trying to handle collisions between non-rectangular sprites would benefit greatly from this! Hopefully Rich or someone else who knows the framework well can give us some clarification on this! 
Btw your artwork / animations are awesome! 