Use bindfs and mount remote folder.
DiskStation> mount
/dev/root on / type ext4 (rw,relatime,user_xattr,nosynoacl,barrier=1,journal_checksum,data=ordered)
/tmp on /tmp type tmpfs (0)
none on /dev/pts type devpts (gid=4,mode=620)
/sys on /sys type sysfs (0)
/proc/bus/usb on /proc/bus/usb type usbfs (0)
/dev/md2 on /volume1 type ext4 (usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0,synoacl)
/volume1/@optware on /opt type bind (bind)
fusectl on /sys/fs/fuse/connections type fusectl (0)
\\192.168.0.102\Public\Music\iTunes\iTunes Media\Music on /volume1/musicBox type cifs (rw)
bindfs on /volume1/music type fuse.bindfs (no-canonicalize,rw,nosuid,nodev,allow_other,default_permissions)
\\192.168.0.102\Public\Photo on /volume1/photoBox type cifs (rw)
bindfs on /volume1/photo type fuse.bindfs (no-canonicalize,rw,nosuid,nodev,allow_other,default_permissions)
/usr/syno/bin/convert maybe replaced with newer version(use ipkg get imagemagick), if it does not work.
sorry for my broken english.