How to make an album collaborative so others can upload directly to my album?
To allow others to upload directly to an album in your account, click the share icon when you are inside of an album.
To allow others to upload to your album you have to check the box that says "Allow anyone with the link to upload". Then click on Save.
When they click on the link they will have the option to Sign up to add photos to this album or Sign in to their own accounts in order to upload to the collaborative album.