Thanks, B!
Of course, I agree that going with an actual actress would definitely be better for the movie's overall quality as a whole.
But as you said, Swift is a good physical match for the role, and even though Supergirl is one of my favorite heroine characters of all time, this is one of those instances where I can let the fact that she's not an actual actress slide, since I think the movie should simply be a fun, light-hearted popcorn summer flick where the main character just needs to be a pretty eye candy and being sexy in costume on the big screen while pretending to be kicking ass, something that I think Swift might be able to do if she was given the chance and of course trained in some acting classes beforehand.
Not that it matters in any way, since it's just an old rumor after all.
And I can't believe that you prefer a Supergirl image where she ISN'T tied up!