The Turing test is not about understanding, it's simply about distinguishability. The idea is measuring understanding is hard, but it's easy to try to distinguish the production of a machine in several parameters by doing a blind test. So a computer may actually "understand more" of something but be blatantly computer-like (by being much better than a human could ever produce) -- a chess expert may identify a top level chess AI that way -- and thus fail the Turing test. So it's more of a sufficient but not necessary intelligence test.

Those photo modifications kind of fit into that theme: if you can't distinguish the filters from real art, they passed an indistinguishability test.