I don't added images to my book strictly because of the size. To add a 1MB image to a Book that is already 3 MB, creates and extremely large PDF Book.
However I believe you have a slightly greater ability to manipulate the image if you place it in a Text (smart story) than if you import it from media.
When I write summaries of my research, I cut the section of the document where the information is located, paste it into my Word Perfect document, and then expand it for max readability. I obviously add all of the reference data as text in my document.