Some devices allow Snapseed to access storage apps like Google Drive, Dropbox, etc. to open photos. If your device is compatible with the transfer process for a particular storage app, the app icon will appear each time you tap Open.
If your device has a storage app installed, but the app icon does not appear in Snapseed's Open menu, then unfortunately there is not a way to access photos stored within that app. The best option is to save the photo from the app storage to the device's internal storage before returning to Snapseed.
- Go to Settings > General > Restrictions.
- You will be required to type in your device's passcode.
- Once it is typed in, go to Photos.
- Make sure that Allow Changes is checked.
- Enable Snapseed in the list.