Unlike a lot of other species, who didn't get it at first but saw the appeal once exposed to it, Coluans do not comprehend human photo culture. They don't pose when their picture is taken, instead acting naturally while remaining in frame (which is what they understood the request to be), and don't really get the significance of why everyone else is standing still, facing the same way, and emoting.
Similarly, if you ask them to take a photo of something for you, the result is usually terrible by human standards, as they don't take anything into account except whether the image clearly shows the subject or not. Culturally, they've never treated photography as art, so they don't attempt to make a pleasing composition for what is "obviously" (to them) just a reference image.
There are more than a few Legion photos where someone has held Brainy in place and he looks a little annoyed as a result.