Well I just retrace the animations. If the outline is equal all around I just use the outline settings for the shape, like for the body in this case. For the mane its 2 shapes, one above the other. I use Inkscape. You draw the bottom shape, copy it and paste it at the same location and hit ctrl+( to shrink it a few steps, give it a different color and adjust the path to get a varying thickness of the outline.