Re: New internet standard...
Yay! - new standards!! Who doesn't love a new standard?!
It does seem like the kind of information that could easily be embedded in any EXIF-like data. There'd be no need to remove it unless you were doing something nefarious, but there's no way I know to put an image on the internet and not have it readily 'stealable' by those with more than no knowledge.
The browser could readily display the relevant copyright and licence data on an attempted save / copy of the image.
There is also a lesson for the students (and frankly the school staff) regarding copyright and what is actually permitted use. Ignorance of the law is no excuse and all that - nor whether or not you agree with the law, sadly so in some cases!