Tahoma2D is Open-source free. The program has some very nice features coming from Ink n' Paint of traditional animation.
This is a small test, using a second monitor to shed animated light on a stop motion set.
I created some frames in a separate layer and randomized the cells distribution in the x-sheet, so it's not really animated.
Put its column on a peg bar and attached a camera to the peg as well. Moved the peg out of the view of the camera stand, and started grabbing the puppet frame by frame in another column with the Stop Motion control in Tahoma2D. The animated "light" layer automatically advanced one frame at a time, as I animate the puppet. Should I choose to delete a frame and go back to recapture it, the light would follow the timing.
The result here is not the best but it clearly shows that it can be used, for some ambient light movement.
Using a projector works far better for animated Gobo's and specific detailed light effects.