In Star Wars Rebels season 3, episode 10 : An Inside Man we see that Thrawn has collected a series of images, mostly of the crew of the ghost and their past (some I recognise from previous episodes).
However, there is one image I don't recognise anything about and was wondering what is known about it; it depicts a fairly interesting looking scene. At a guess it appears to be a Sith attacking Jedi and supporters. Has this picture (or something similar) appeared earlier in the series or has anyone said anything about it outside the show that might clarify this?
I've added a screencap to help: