> attempt using FFMPEG before resorting to manual screen capturing. Maybe. If each "slide" was displayed for several seconds, ffmpeg would capture hundreds of essentially identical frames before the video moved onto the next "slide." The OP would have to wade thru thousands of files to find a few unique images. Is there something like the "diff" command for image files? > the photographer may actually retain ownership While that may be true (and I'm all for supporting creative artists), it would not trump fair use. See http://en.wikipedia.org/wiki/Fair_use Fair use is a limitation and exception to the exclusive right granted by copyright law to the author of a creative work. In United States copyright law, fair use is a doctrine that permits limited use of copyrighted material without acquiring permission from the rights holders. Examples of fair use include commentary, criticism, news reporting, research, teaching, library archiving and scholarship. It provides for the legal, unlicensed citation or incorporation of copyrighted material in another author's work under a four-factor balancing test.