I need to add a custom field (a simple text field) to the image_field widget in Drupal 7.
The structure is a standard node (called Article) which has zero or more images (related photos or graphics) attached via the image_field widget. The field I want to add is the source of the image, and is used later to figure out when it needs to be deleted.
I've tried the code from this post, but couldn't get it to work.