As with anything drupal, there are a million different ways to do something. I am asking this question for 1) Because I actually have to do something similar and 2) Because I would like to know all the different ways this could be achieved and the pros and cons of each. Is creating a custom field the way to go or should you just dump some dynamic code in the node-album.tpl.php template? Which way is the most flexible? Which is the most non-coder friendly?
Scenario: You have two content types (say, photo and album) where photo has a file field for an image and album is a collection of photo nodes.
If a user is viewing an album node type, how would you go about creating a "add photo" link on the full node view to add a photo to that specific album? Using the entity reference prepopulate module.
So how would you give users a way to click on a link/button for: