It is actually highly unlikely that the company has the legal right to make a "copy" of the work, which would include taking a photo of it, in the absence of a "fair use" exception. Please note that this would still be true even if they had purchased the work, unless they had also specifically bought the right to reproduce it. The right to copy a creative work remains with the creator unless and until the creator transfers the copyright, and a standard purchase does NOT include the transfer of the copyright.
Good luck to you in your artistic endeavors.
Any answer or other information posted above is general in nature and is not intended, nor should it be construed, as legal advice. This posting does not create an attorney-client relationship between you and the posting attorney, and you are urged to engage a qualified attorney who is licensed to practice in the relevant jurisdiction.
The company made a wise business decision in order to avoid committing copyright infringement. You are legally entitled to ask and they are legally entitled to turn you down and NO, they are not being lazy, they are being smart.
So far, this is free to you. Until you pay a fee, I am not your lawyer and you are not my client, so you take any free advice at your sole risk. I am licensed in IL, MO, TX and am a Reg. Pat. Atty. so advice in any other jurisdiction is general advice and should be confirmed with an attorney licensed in that jurisdiction.
While the other answers provide sound information, frankly I'm confused. If what you are saying is that you submitted some of your own artwork in hopes of some compensation if it was selected and your work was rejected, then what do you mean "art they chose"? Is there something else going on? Sorry.