Think a limitation of screenshot is that you can only do one per tick (frame), so you will have to make a way to somehow wait for tick to happen.
We solved this by having the python bridge run a method in tick that we implement in the python class to return next for generator functions. Not fully clear on the implementation but allows us to run
for _ in TakeMultipleScreenshots():
yield MyEnum.WaitForNextFrame
Think I’ve seen that you can attach functions as callbacks to slate which to me seems like a much better solution but our method worked so haven’t touched it since.