Either creating worksheets, constructing games, enriching presentations or writing in blogs teachers and students need to use images for their projects.Today there are numerous public domain image galleries online that offer royalty free digital pictures. Here are some which I have often found handy when I need free copyright images for educational purposes. I cite them in two categories:

A for more general interest images and B for education oriented ones.

A.  general interest image galleries

1. Office Microsoft gallery is always my starting point but if I don’t manage to spot what I am looking for, I know there are other resources too.
2. Pixabay  Photographs and clip art of great variety. Be careful though: the first row images are sponsored images and these are not free. Only the images on Pixabay -the second row onwards- are free and bound to Creative Commons Deed CC0
3. Public Domain Pictures.net is a repository for free public domain images. Some photos do require a model or property release if they are meant for commercial use
4. 4freephotos I like the architecture and textures categories. Be careful again: the last row images are sponsored images from Shutterstock.com and these are not free.
5. Wikimedia Commons – nearly 19 million freely usable media files(sounds and videos too), although some media files require the owner to be cited
6. Public domain images Not copyrighted, no rights reserved
7. Public domain photos free photos and clip art images
8. picdrome.com    a Public Domain digital photography collection, free of copyright and licensed under Creative Commons CC0 1.0 Public Domain Dedication.
9. clker.com The online royalty free public domain clip art
10. morguefile.com Check the free photos archive

B. education oriented image galleries

1. Pics4Learning  A rich gallery specifically oriented towards teachers and students
2. Teachersfiles.com free educational clip art for teachers among other resources
3. Openclipart.org  free clip art for teachers and more
4. Classroomclipart.com   a Source for Free Clipart, Clip Art Pictures and Illustrations. Images in the Classroom Clipart collection may be used for Personal Use and also for Educational Use by Students, Teachers, Parents in print, multimedia, and video productions. Uses include school projects, web pages, newsletters, bulletin boards, posters and presentations. When using the full size of the image or the thumbnail size of an image on a web site, a link must appear near the image.

IMPORTANT

Although most of the above sites do not require a link back to their home page, there are some which do, so always check the site for appropriate attribution, if any is needed. In any case a reference to any source site would be nice.

Be aware that pictures featuring products should be used with care.