This is wasting our time. Are there no rules when people are taking pictures OR People who put these Batches together.
Often, photographers took duplicate images on purpose, in case of poor focus or difficult-to-read original images. Remember that many of these were taken MANY years ago with microfilm cameras that were not sophisticated. No autofocus, often in difficult lighting conditions. I have seen examples where it is obvious the page moved - I suspect sometimes the photographer was working in a room with an open window because the weather was HOT. With a little breeze, the page moved. So, he (or she, later) took an extra shot to be sure of having a good image for us to find all these years later.