
creative commons licensed (BY) flickr photo shared by jensenphotos1
Copyright exists to give artists the freedom to share their work and to build upon what has been created. There are many images available on the web but not all of them are free to use or to build upon.
One way to locate "free" images is to filter a Google Image search with the Usage right of "Labeled for Reuse". Another is to use sites that make it easy to find images. Several are listed here.
If an image is in the Public Domain, it is free to use without giving credit to the creator or to the site where located. Many images are Creative Commons licensed minimally with "Attribution" requirements which means you need to name the creator.
Here are a few ways to credit an image. The attribution should be as a caption beneath the image.
creative commons licensed (BY) flickr photo shared by jensenphotos1