Caption: A reader should not have to refer to the text to understand the image. Explanatory text should include title, owner/artist and where the image is stored. In APA you must provide a copyright attribution in addition to citing item when you reproduce it in the body of your work. See Publication Manual of the American Psychological Association, 6th edition, 2.12. p. 38. For educational projects, look to instructor's instruction for further guidance.
Emery. A. (2016). Flamingo photograph. Licensed under Creative Commons Zero on Unsplash.com
Determine if you can use image ethically. Did you find it via a search engine? Find the original source. Find images that have copyright and other information so that they can be used legally.