the first pic shows him before the getsuga....so up to this point the shadows are normal.
when the getsuga is released, a burst of light is displayed. This light falls on every spot of his body since he doesn't have anything in front of him to cover parts of his body from the lighting.
So when the blast is released, the parts of his body that didn't contain shadows brighten up heavily since the getsuga was released about 1 meeter from him.
and another colo