The reference that you use depends on the type of image and what citation style you are utilizing.
If it is an image of a painting, sculpture, or photograph, then refer to the instructions provided by OWL Purdue for MLA.
For a digital-only image, refer to these instructions provided by EasyBib. Again, this is only for MLA.
For APA, OWL Purdue offers this instruction when citing an image in a presentation. To cite tables, figures, and graphs in APA style, follow these recommendations.
Use these links to view Purdue OWL MLA Citation Guides and APA Citation Guides.