I am working on a website where the user can upload a post relating to a location and then they can add two or three photos to go along with it. I understand how to do a ba
That's what BlobReferenceProprty is for. You can add a reference to a blob into model which seems to be what you want.
Here is a full example of uploading photo and associating it to user.
To associate users and photos it uses creates class UserPhoto
that links user ID and photo blob keys.