it is 7mb
The size of the file is not an indication of overall quality. Indeed, if it was too small Adobe wouldn't even have allowed you to upload it. Quality has to do with correct exposure, sharp focus, lack of noise and chromatic aberration and other artifacts, as well as composition.
Don't upload in B&W. Customers can add their own effects.
Have a read of this. It's a brief guide on image quality:
1. black and white photos do not pass moderation
2. The photo looks quite noisy even without magnification
3. lions occupy a small area in the frame and a lot of extra empty space
Black and white.
Too much empty space.