This is a handy and efficient technique to get a lot of photos added to a Web app quickly. And since the Dropbox iPhone/iPad app is free, you can upload images right from your smart phone camera. So your end user can upload a bunch of images right from the field.
Watch the video to see how Bob sets up this integration and how you can even automatically resize the images, generate thumbnails images, and more. By the way, this isn't limited to images. The fact that you have Dropbox integration opens up a whole bunch of collaboration opportunities for your database applications.