When I was in high school the vast majority of my peers understood how to bundle up a bunch of photos, documents, etc. into a zip file and e-mail them. This is because my peers were nerds, and we were excited about this new computer technology and eager to learn everything we could about it. There were no computer classes in high school. When we had high school science class, we were expected to draw pictures of our experiments (y'know, with a pencil, on paper) and fill out the lab report longhand. There was a large segment of the student body who had no idea what a file was, or how to turn a picture into one, let alone how to bundle it into a zip file.
It was a bit different in college, where we were expected to understand Excel and how to run a regression or graph some data. But then, that drew from a very different population than high school.
It's sorta like how SATs are dropping not because kids are getting stupider, but because a larger proportion of people who would never have been considered college-bound a generation ago are now expected to take the test.