If you take a picture, you do own the copyright to that picture. But the copyright to the work of art (painting, sculpture, etc.) may be owned by an artist who created the work of art. Thus, your work is a '''derivative work''', and unless you have permission from the copyright owner of the work of art, it is a '''copyright violation''' if you try to do certain things with it. For instance if you try to sell your picture.
To be clear: if the '''artist holds the copyright of his/her work''' (or someone else owns it by inheritance, sale, etc.) then in all likelihood '''you cannot upload it to WP Commons!''' The caveat there would be if you received written permission from the copyright holder of the work of art to allow you to upload it under a free license that allows for a variety of uses, including commercial use.
'''Fair use''' may apply. But, '''WP Commons does not allow for fair use images''', so no fair use images can be uploaded there. '''You can only put fair use images into Wikipedia.''' To make a fair use claim, you would have to discuss the topic in the article, and to cover the intent of the fair use exceptions under U.S. copyright law. Also you will likely need to limit the images to only a few lower resolutions images of the artwork. The proper licence for these kinds of images is {{tl|Non-free 3D art}} (that template clearly states that a fair-use rational must be used.) Further, the images '''MUST''' comply with all 10 [[WP:NFCC|non-free content criteria]], which preclude using galleries under the minimal use criteria.
However, not all artworks are copyrighted. Just like any copyrightable item, works of art may not be covered due to several issues:
