So....I have a UI design question I need to work out before I work on my Drupaler thing any more...that is, if anyone still finds it worthy of being created. If not, just let me know. There are plenty of another projects I can play with instead.
But, if I should continue to work on this, the question is:
How should the user select photos to add to a collection?
Drupal gives you the ability to dynamically add multiple instances of the current field. In the picture below, I created a dummy content type, added a single field of type "Decimal", then edited the "Number of Fields" to "unlimited." These fields are rearrangeable using the stock Drupal UI. No fancy needed.
I could use this same approach with a widget that lets you select a single image. And let the user add as many as they want, shuffle them around as they want, etc. But is this good enough for our purposes?
I was going to make a full-blown, complicated AJAXy widget which would let you do all this. But is there a need to? If you (anyone) has the time, try creating a dummy node that has some field with unlimited cardinality (I believe that's the terminology used in the code). If having multiple instances of a field which lets you select a single, existing image seems good enough, I'll go that route.
What say ye? (If I lost you, I'd gladly try to clarify.)