Hi Marche,
Memory Maker is a fantastic service that offers the convenience of having someone else take some great family photos so that no one is missing from those treasured memories. If you purchase the Memory Maker in advance, be sure to link it to your My Disney Experience account. Then, when you arrive, it should be linked to your MagicBands.
As long as everyone in your party is linked to your My Disney Experience account as a friend or family, all of their photos will be linked to the Memory Maker, as well. However, only the person that purchased the Memory Maker will hold the "entitlement" and be able to download everyone's photos. The others in the party will be able to view them, just not download them, unless you change who will hold that entitlement.
I hope this clarifies it for you. For more information on Memory Maker, click on the link I provided above. Have a wonderful trip and say "cheese!'
~Allison L