Even if it's just duplicating the same frame two or three times. You only have a four step morph here, not enough for animation. Ideally animated clips should run at least at 24 fps, this GIF seems to be running at 12, but even then, that means the entire clip flashes by three times in a second, which reduces a nice sequence to an episode of flashing siezure theatre.
Thanks for the contributions though, try some SW
.