I'd like to say you're showing good example that Bitcoin aren't only used for investment or criminal activity.
But I guess it can be hacked by replacing your own qr on the pic with photoshop, then post it online as Banksy or other famous guys... That's why I attached my website to the qr to be able to verify the donation address. We should find a easy and secure way to verify that the donations go to the right address.
Not exactly 2 years, my first was in nov '17.
It's pretty much impossible since Bitcoin is decentralized, unless centralized service (which record Bitcoin address of public artist, services, etc.) is involved.
I doubt there's any idea which is better than yours (in this case) without centralized service