APA style does not give explicit instructions for crediting images that are reproduced in a work, rather than merely cited . What follows is therefor only a suggestion. If you are unsure of how to credit an image, please consult your instructor.
For images that are in the public domain, state that explicitly.
Figure 1. Map of the Kamloops—Thompson—Cariboo Electoral District, by P. Simon, 2008, http://commons.wikimedia.org/wiki/File%3AKamloops%E2%80%94Thompson%E2%80%94Cariboo.png. Public domain.
If the image is being used online or in a PowerPoint presentation, the hyperlink may be anchored by the text:
Figure 1. Map of the Kamloops—Thompson—Cariboo Electoral District, by P. Simon, 2008. Public domain.
The corresponding reference would be:
Simon, P. (Artist). (2008) Map of the Kamloops—Thompson—Cariboo Electoral District [Digital image]. Retrieved from Wikimedia Commons website: http://upload.wikimedia.org/wikipedia/commons/2/2e/Kamloops%E2%80%94Thompson%E2%80%94Cariboo.png
For images used under a Creative Commons License, give the URL of the specific license -- there are many different licenses, and the differences among them matter a great deal!
Figure 2. Yellow-bellied Marmot Pups - Kamloops, BC., by A. Vern, 2007, http://commons.wikimedia.org/wiki/File:Yellow-bellied_Marmot_pups_-_Kamloops,_BC..jpg. Used under Creative Commons Attribution 2.0 Generic License: http://creativecommons.org/licenses/by/2.0/deed.en
If the image is being used online or in a PowerPoint presentation, the hyperlinks may be anchored by the text:
Figure 2. Yellow-bellied Marmot Pups - Kamloops, BC., by A. Vern, 2007. Used under Creative Commons Attribution 2.0 Generic License.
The corresponding reference would be:
Vernon, A. (Photographer). (2007). Yellow-bellied marmot pups - Kamloops, BC [digital image]. Retrieved from Wikimedia Commons website: http://commons.wikimedia.org/wiki/File:Yellow-bellied_Marmot_pups_-_Kamloops,_BC..jpg
If you know the real name of the creator, use it. Otherwise, use the person's screen name.
Figure 3. Old Kamloops Courthouse, by MelvinMelvinMelvin , 2012, http://commons.wikimedia.org/wiki/File%3AOldKamloopsCourthouse_8933_Crop.jpg Used under Creative Commons Attribution-Share Alike 3.0 Unported Licence (http://creativecommons.org/licenses/by-sa/3.0).
If the image is being used online or in a PowerPoint presentation, the hyperlinks may be anchored by the text:
Figure 3. Old Kamloops Courthouse, by MelvinMelvinMelvin , 2012. Used under Creative Commons Attribution-Share Alike 3.0 Unported Licence.
The corresponding reference would be:
MelvinMelvinMelvin. (Photographer). (2012). Old Kamloops Courthouse (digital image). Retrieved from Wikimedia Commons website: http://commons.wikimedia.org/wiki/File%3AOldKamloopsCourthouse_8933_Crop.jpg