What image? From where? You need to provide much more info.
I am having trouble understanding what you are saying, but it sounds like you're saying the original footage you are trying to import is 1280x720, but when you import it it is 300x280. If that's the case, it sounds to me like you have a stock image library (like Action Essentials from VCP) and you're importing the thumbnails instead of the full-frame video file. So double-check that you are importing the right asset.