Open Pics provides an invaluable service, searching through millions of open-licensed pictures on digital libraries from New York City, the Library of Congress, "LIFE" Magazine, and more. With the tap of a button you can find and use images from throughout the last two centuries from the streamlined interface of this very useful iPad app.
The app is designed to be as minimalistic as possible. Open it and you're presented with a black screen and a white search box. Type in your query and choose the library in which you want to search, and then press "Enter" and "Search." Images appear almost immediately and the endless screen loading style means there are hundreds or even thousands of results to sort through for any single query. Sharing options are fairly limited, allowing you only to post on Tumblr or download to your photo library; but since you can share from your photo library to Facebook or Twitter, it is a small quibble.
Whether you enjoy looking through old-time photographs or need some images for an upcoming project, the Open Pics search engine for iPad is a very well-crafted, easy-to-use app that will provide all of the results you need for your next big project.