In the 21st century it is entirely acceptable to include a CD ROM envelope at the back of your essay and refer your
reader to it as a visual source. CDs can accommodate thousands of photographs, short videos and sound files.
Make sure you refer to the reader to clearly labelled files on the CD.
You could also offer the reader the option of reading an electronic
version of your essay, also on the CD, with hyperlinks to appropriate
files. Any material taken from external sources must be referenced in
your bibliography.