Some number of years ago, I worked on a LIMS project for a customer who needed to track unique product records. Some of the information that defined a product as being unique were LIMS fields but one element was the version of the blueprint of the product. Unfortunately, at the time, there was not a method in which to differentiate between pictures and we were not able to have the system determine uniqueness without a person to verify the difference in drawings.
Fortunately, technology changes, and it sounds as if technology has caught-up with this issue, but, too late for my customer from years ago, unfortunately.
Recently, I ran into someone from Cilia, which is a document storage company. He was telling me that this is now possible. In fact, one of their products does track photo differences. While I have not used this product, I want to put its link out so that those of who might have a similar issue might have at least one product to begin with:
http://mycilia.com/
Gloria Metrick
GeoMetrick Enterprises
http://www.GeoMetrick.com/