If the company can expand to specific features for photos, more of which are likely, there are other possibilities for the many other types of files that users add to Dropbox.
Files can be opened with the included Inkling Sketch Manager software to edit, delete or add layers as well as to change formats and transfer the files for adjustment and editing in creative software applications.
If you want to sell direct, then you can upload your ebook files and Ganxy will, after verification, add a direct sales link to your other retail links.