I love Simple Image Gallery Pro and will absolutely continue using it. But I'm building a site now and need it to do more than it does now. Basically the site is like a Yelp for campgrounds, where people can share information about campgrounds. One of Yelp's cool features is that users can upload photos. Every photo that is uploaded becomes part of a gallery.

SIGP does things a bit differently. Basically, users can upload a gallery via the front-end article editing interface, and if they upload a gallery, it deletes the previous gallery.

What I think would be great would be this:
  1) Users have an "add photo" interface that is separate from the article editing interface, and
  2) Users can add to the gallery, but not replace it, and
  3) If there is no image associated with the K2 Item, an image from the gallery can automatically slot in.