APA (American Psychological Association) Style is used in Social Science disciplines, like Psychology and Education. Always consult your assignment or ask your instructor for the correct citation style to use
The image source would also be included in the references list at the end of the slide show or essay.
Sample article with DOI:
Bailey, N.W. (2012). Evolutionary models of extended phenotypes. Trends in Ecology & Evolution, 27(3), 561-569. https://doi.org/10.1037/rev0000126
Sample web source:
Canadian Cancer Society. (2013, April 14). Cancer research. http://www.cancer.ca/en/cancer-information/cancer-101/cancer-research/?region=on