I have an image editing app where users can apply effects to photos. How could I enable it so that users can see my app in iTunes in the File Sharing tab and then just drag+drop photos to the app?
Some of the eBook readers like Stanza works like this and it would be a cool option. Maybe someone can point out a tutorial or resource that talks about how to enable and use this technique.
You just have to set UIFileSharingEnabled (Application Supports iTunes file sharing) key in the info plist of your app. Here's a link for the documentation. Scroll down to the file sharing support part.
In the past, it was also necessary to define CFBundleDisplayName (Bundle Display Name), if it wasn't already there. More details here.