Everyone has their own way of providing for extra documents. We've generally ascribed to the methods Pauline has used, for much the same reasons. Extra copies really don't take up much space at all, and we can put copies of all of those things in each of our bags. After all, the copies of the passport page are really only good for identification; if you need a replacement, you're going to have to have some kind of identification, and the actual photos as well in order to get the physical replacement. Downloading to a smartphone, or other device may be technologically correct, but you still need a device to access it. That's extra weight and extra devices. and what if the device is stolen or damaged? if you've put all your eggs in one basket, and you lose the basket you have none. But if you spread your eggs around, you'll at least have some if you lose one or two. We go for the old-fashioned physical copies of the documents in various places.
We've never carried copies of prescriptions( we do take several lists of credit card numbers with the collect numbers to be used overseas ), but it can't hurt. As pauline has said, it doesn't take up much space, and you're covered. But we are now going to add an extra set of passport photos to our list of emergency documents, just in case. Photographs on a smartphone may be technologically correct, but aren't s much use as the hard copies will be if you need a replacement passport.