IAD uses the APA citation style. Hover over the "Citing Sources" tab to see a page just for APA in general and a link out to Allison Cywin's guide for citing images.
See the other boxes on this page for help generating citations in databases and managing citations.
Part of researching is having a strategy on how to manage all these resources/citations you've found. You can use a citation management tool like Zotero to organize citations to sources, collect digital files such as full-text PDFs, and cite sources automatically when writing papers.