Grabbing images from the internet is easy - search, copy and paste. But how do you know if you have permission to use someone else’s photos? To be a good digital citizen, you need to look for royalty-free images that are OK to use in your projects.
Here are two resources that are a good place to start:
Free Photos For Education
An extensive collection of public domain images available for free download and use.
High-definition imagery and virtual tours from hundreds of museums worldwide