I am trying to find an easy way where I can have users submit photos/audio/files from their smartphone to a host on a file server. The easiest way I can think of would be to set up an SFTP host and find an app that adds functionality similar to how Facebook and various other apps have a dedicated "Send photo to Facebook" except it would "Send to folder XYZ".
I have not found any way to do this. Does anybody know of an app that can do this or something similar? Or any other ideas to achieve the same result?
I have not made a choice on hardware, so iOS/Android/Windows Mobile are all options.