There are really only a very few ways in which images are made, and expressed in the world, whereas with the course's counterpoint "sculpture" there are probably hundreds.
A quick review in the class we came up with they ways images are shown, or made:
Projections, cinema, television, internet, mobile phone (tablets etc), and images made with light (holograms?), and through the computer ( and all the file types and digitization that correspond to that production). X-rays, MRI scans, CT scans and CAT scans are some medical image types. Then there's the cellulose/plastic substrate the image is printed on, transparencies, etc.
Paper based productions: newspapers, magazines, labels, photocopies, prints, books, all print material in general (maps, pamphlets, stamps, postcards, tickets, blueprints), advertising signage, billboards.
Museums, and libraries are host to images, as are the sides of buildings, buses, and cars, Human bodies too with tattoos.
Caves, rock petroglyphs, parchment, papyrus, sand mandalas are other forms of image making. We didn't discuss these as of yet.
Most of these are rectangular in format, and rather 2 dimensional, with the exception of forms replicated on natural substrates.