The issue I have with paper wallet is that it can get lost/destroyed in a fire/stolen, etc.
Create a few copies and store them in different locations. As for locations, store them in/at where you least use. E.g. Inside of a wall clock.
Same with any hardware backup (hardware wallet, hard drive, laptop) that stays in one physical location.
Like paper backups, you can create a few digital backups too! A few USB or CD or even floppy disk etc...
I personally trust the cloud much more to ensure that the data will be there several years down the line.
You are essentially entrusting your seed to others. And what make you sure that it is safe as long as you store them in a cloud? What happens if something happens to their hardware? Or maybe their service in no longer available? Or they are hacked? Or worst, they check your files? Of course, most of the cloud make backups, files are encrypted and they have done everything they can to make it better. But nothing is certain...
Paper backup vs digital backup vs cloud backup vs <insert anything> - One is not better than another. All has their own advantages and disadvantages and the main thing is, it depends on the person and the way they does it.
As for remembering which file contains what, I guess it would have to be relatively easy (for a person, not for a hacker bot) to understand it. If it's a photo of me holding a piece of paper that says "dog", then it's the word dog, etc etc. If there are 12 files in a folder, it should be fairly easy to reconstruct the 12 words, and offer a higher protection than a single file that contains the private key.
You can add irrelevant photos in that same folder and using related photos rather than exact representation of words, such as "dog food" instead of "dog", improves security. Adding photos and splitting them into different folders make it even better.
You may now think, "if it is done as you said, how can we differentiate between pictures of words of mnemonic and irrelevant pictures?" To counter this, put a "dot", "underscore", "shapes - circle, square, rectangle,..." or inconspicuous characters like semicolon in an inconspicuous place of your photos. You can use it just like using different colors described below. Don't forget to adjust colors and opacity/transparency of shapes to match background!
Although I do accept that all this may not be necessary as strong encryption will be enough.
You can also use other methods. For example, put your seed in a huge number of words with different colors jumbled together. Don't use "1 color per word" rule here because you will have to remember which color to find words. It may get very confusing! Rather, use 15 or so colors, and use 3-5 colors for seed and remaining for other colors. Just repeat colors! You can also increase number of colors according to number of words you put together. There are lot of designs online. It is not hard to create one.
