There are two ways for multiple people to upload to the same account:
  1. Create an account and share the login and password among your friends.  However, if you and your friends have a falling out, one person may change the password and lock the others out of the account.
    Set up a dotPhoto album in your account that allows guest uploads.  In any album, choose OrganizeAlbum Settings, click on Allow Guest Uploads, and Save. This will enable your friends to upload to only that album, but they will not be able to delete photos.  As the "owner" of the album, you will control which photos remain and which are edited.