Archive notice: This article was originally published on January 19, 2016. Links and embedded videos are preserved as part of the historical record.
The copyrights on the works have now expired, so all images may be reused however desired without permission and, according to the New York Public Library, may also be altered.
Here you can find the complete digital image database with around 700,000 items. Simply select the public-domain images using the search filter and happily browse the remaining 180,000.
The New York Public Library regularly expands the database. All further information about the public-domain material is available here.
