If its 1 frame, I would say its not an animation but they don't specify whether an animation consists of one additional frame (so total 2 frames) or 2 additional frames.
You can string together animations like idle -> walking -> running etc but all of these may only have 2 frames. You are not allowed to string together two running animations to make it have 4 frames though, for example. So what you showed in your screenshots is allowed.
