The paper shows dogs with very distinctive fur coloring. Particularly the corgi with a white strip between its eyes. I think the paper would be completely fraudulent if this dog were also featured heavily in the training set. So the point is the white stripe corgi isn’t in the set, and with a few examples, the model could then generate brand new images of corgis with a similar fur pattern. Maybe all it can do is fur patterns but it’s a start.
My point is that it is difficult to judge (for us) that the returned photos are actually similar to the subject.