Citations can be formatted according to the citation style you are using (MLA, APA, Chicago Manual of Style). Using images that you did not create require citation in all cases and the citation should be accessible in the context of the image's use.
Here are a few basic guidelines:
- Give attribution to image creators in citations and credit statements to acknowledge authorship
- Indicate when using a personal photograph
- Include source information
- Citations to images included in image databases should include the following (or as much of it as can be easily determined from the source):
- Creator's name;
- Title of the work, as given;
- Location of the work (museum, library or owning institution, if known);
- Database collection, if known;
- Rights information, if known.
Thanks to Simon and Fraser Univ for providing up-to-date guidelines on in-text and bibliographic citations of images in their Finding and using online images: Citing Guide
and to Univ. of Cincinnati https://guides.libraries.uc.edu/citing/images for providing these examples of image citations