Going back to your original comment, I just thought of another theory. Maybe it's a NEW magazine starring Fluttershy in disguise! What if Photo Finish came back to Fluttershy because she couldn't find anypony else with her caliber of gracefulness? Fluttershy only agreeing to model for her after excessive begging and only if she could find a way to guarantee that Fluttershy wouldn't get any unwanted attention. Thus, the color changing and wing concealment began!