It's very easy, you just need to define new image, in the default Ren'Py way. No tricks, no advanced coding.
If you mean stuff like
image ion
FilmStrip('content/gfx/be/filmstrips/ion.png', (192, 192), (5, 9), 0.05, loop=True)
FilmStrip('content/gfx/be/filmstrips/ion_1.png', (192, 192), (5, 9), 0.05, loop=True)
then it's not gonna work because animations should have different positions and zoom.