Those wings aren't even close to a butterfly's. The shape and the nervature are completely different. Look at the front edge of the forewings. Butterflies don't have that kind of frame. Look at the aft wings - they're fan-shaped, which means they fold ove the abdomen. Butterfly wings don't fold.

It's not unusual for a mantis to have wings. All insects have wings, but most just don't use them. Even swimming and burrowing insects have wings. Even ants have them.

This photo is not a fake.