- Share — copy and redistribute the material in any medium or format
- Adapt — remix, transform, and build upon the material for any purpose, even commercially.
- Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
The State Library of Victoria has a search function solely for copyright free images. Any image that is copyright free has its reuse requirements in the caption.
The British Library shares images from the 17th, 18th and 19th centuries via their Flickr feed. With some images, you can follow a link to the original book.
The United States’ Library of Congress has a database of free to use and reuse images. Acknowledgement requirements are on each item.