This video is an introduction to images, whether they are photos, diagrams, drawings, paintings, scans or other pictures.
We add a photo to a blog post and also mention the use of other people's images that have been released under a Creative Commons licence. One place to find these is by searching Flickr, the photo sharing website.
Incidentally, you can license your own work under a Creative Commons licence, whether that be photos, video or text. There are many reasons why you might wish to do so.