Image upload only works if user has full storage access

[Fensterbank]

The script tries to upload the contact pictures to /$usbdevice/FRITZ/fonpix/.

When I create a restricted user just for this script who only has access to the fonpix folder, this folder is the root of the FTP file tree, so uploading fails because the designated upload path does not exist.

The script should made more intelligent in reading the available file structure. We should avoid to define more config values for this cases.