Years back we have photographs and books. Even though they are fragile and clunky but they still last a very long time. You can see examples in movies like Terminator (a photograph).
We have seen photographs that are more than 100 years such as the ones we see in the following sites:
Nowadays, we see more and more of these photographs turning digital (mostly jpg). Twenty years ago, when we see a .doc file, we use WordPerfect but now we use Microsoft Word. However, when you use Word to read the file created using WordPerfect, you will not be able to interpret it properly.
So what happens JPG in 20 even 50 years? How about the media it is stored in? Will it last? We now have hard disk, and thumb drives but previously we were using floppy disk but now newer computers no longer support the drives to read these media. Will we be able to read our media then? Even if the media can last, will we be able to read from them?