Earlier quoted context omitted.
Because I'm a fan of the gift economy. This was the way the Internet used to be when it started. This is the spirit that's common in academia, but has sadly waned once the internet got commercialized and grew out of control.
Back in the days of the early internet it wasn't free to host images. You paid for a web host, had your own site, and hosted what you want. But you paid!
Like Wikipedia. There are costs to run it, but it's free to use.
Same with public libraries.