It's weird, the two sides actually do seem to match better when you look at the painting by itself. The perspective of the live plate just messes with the perspective of the painting. (Though I would have assumed it was painted with the live plate being projected for reference - so wouldn't the live plate perspective have been incorporated into the painting? Harrison Ellenshaw did other paintings in the film with perfect perspective, not sure just what happened here...)

But it's far from the worst mangling of perspective and proportion - ever seen the paintings in Star Trek: The Motion Picture when they're exiting the Enterprise to walk to V'ger?

Somewhere, Escher is in a corner crying.

And I especially like the profile view of the saucer that makes the crew look like giants...can't find a picture of that online...