To get a small edit of good pix, or even just one, a photographer takes whole series of images. Anyone stealing the best photo(s), off the web say, wouldn't have the stock of off-shoots that the original photographer would. So it's worth keeping a lot of digital stock for this reason (and a few others I can think of but that's not the question). If you're a known photographer, have a recognisable style, or the work has already been published and properly credited, is stocked with an agent or agency, it's less of a problem?