Is it possible for a CD burned on a Macintosh (burner make/model unknown) to be read in a PC CD-ROM drive? The files burned to disc will be JPEG's.

Try ZDTv "Call of Help" I'am sure good old Leo will help you, but anyway being he to slow here your answers to the questions.
In order for the CD to work on the mac & windows it will need to be burned using ISO9660 format & here one on Joliet extension http://www.tempel.org/joliet/