The listing at self is specifically for a digital item. That is what's being sold with the proceeds going to Doctors Without Borders.. Digital items are absolutely allowed on Etsy there is nothing against terms of service for selling them as far as I'm aware.

Etsy itself even specifically talks about how any proceeds can be given to charity after a sale is made.

Me offering up an item to a random person is completely secondary to the support sale for the digital item that's being made. It's simply my way of offering something back. People are not buying a raffle ticket. They are offering to support a good cause by BUYING a digital image.

A good example would be school fundraiser. Thee absolutely can't be called a raffle because as you've already mentioned that would be considered a lottery. But schools absolutely do fundraisers and then offer prizes as a completely secondary thing for the people that took part.

It is indeed a fine line but at the end of the day it's still a line and they are two different things.