When searching for images to use in your projects, it is important to understand who created the image and how it came to be online. Older works in the United States (created before 1923) are usually considered to be in the public domain, while newer works can be safe to use if the creator has made clear how they want to share them - either with Creative Commons licenses or waiving their copyright. Some images, while within copyright, can be safe to use within fair use, such as for a class project or presentation. Remember, even if an image is free and unrestricted to use, it's always a good idea to cite your sources! See below for more information.
Below are resources via Penn Libraries. Images found through these sources may be under copyright.
Don't remember where you found a digital image? Try a reverse image search:
Public domain images are free to use and reuse because they are not protected by intellectual property laws. In many cases, they are older works with expired copyright. In some cases, creators have actively released their works into the public domain, making them openly available for use. Usually, works produced before 1923 in the United States are considered public domain.
The resources below are free to search on the open web and can be good starting places.