When Dropbox, as a company, focuses on constant useability options and keeping customers engaged, a nice-to-have and attractive feature would be to add automatic Pan & Zoom functionality to a folder containing photos you wish to view in a Slideshow. So many people I talk to want to create this type of slideshow with their photos. Having the option to do so from DropBox natively would be incredibly convenient and keep people storing their data/photos using/relying upon your product more and more.