Only include an intext citation for personal communications including letters, memos, personally conducted and unpublished interviews and electronic messages that aren't publically archived. These materials aren't included in the reference list as they can't be traced by the reader.
Incorporating images, diagrams, tables and maps
The figure you use should be direcly relevant to the content of your assignment and be correctly referenced.
In text: "As illustrated in Figure 20.23, the general vegetative regions of North America can be determined…"
Provide the image with a caption (i.e. Figure 2. General vegetative regions in North America. Adapted from "Map use: Reading analysis interpretation," by A.J. Kimerling, A.R. Buckley, P.C. Muehrcke, and J.O. Muehrchke, 2012, California: Esri Press Academic, p. 457.)
If an online source, provide a link to the URL
Provide the full reference in the reference list eg.
Kimmerling, A. J., Buckley, A. R., Muehrcke, P.C., Muehrcke, J. O. (2012). Map use: Reading analysis interpretation, California: Esri Press Academic.