Before you upload an image, make sure that the image falls in one of the four categories:
Own work: You own all rights to the image, usually meaning that you created it entirely yourself. (example, see below for details)
Freely licensed: You can prove that the copyright holder has released the image under an acceptable free license. Note that images that are licensed for use only on Wikipedia, or only for non-commercial or educational use, or under a license that doesn't allow for the creation of modified/derived works, are unsuitable. (example, see below for details) When in doubt, do not upload copyrighted images.
The Digital Gallery provides free and open access to over 700,000 images digitized from the The New York Public Library's vast collections, including illuminated manuscripts, historical maps, vintage posters, rare prints, photographs and more.