Do you mean to cut away the black boarders that sometimes surround the picture?
Yes, that's a rule we have.

Or do you mean to cut out the car from the picture so it's the only thing seen on the new picture?
Well, I think it's "misleading" to do that, I have seen that some have used this technique to add a number of cars from the same picture or adding something that otherwise would have been considered too background. Also; it was decided a long time ago to not do that since we want the original captures in the database.