How do I credit a photo?
If you retreived the image from somewhere like Britannica Image Quest or Flickr, which usually comes with a Creative Commons licence, you would have already been given the permission to use the image for your projects.
Images for decorative use
If the image is placed on the cover page of the project (or similar 'decorative' use), you would only need to credit it. This credit can be found Screenshot 1 and box #1 in Screenshot 2 (both taken from Britannica Image Quest) below.
Images used to illustrate a point
If the image is used to illustrate a point in the body of the text, you would need to include the credit and a citation in the footnote and/or bibliography. The full citation can be found in Screenshot 2, box 2.
Please see links below for more information on image copyright.