recovery

we used the commands
$ sudo apt-get install recoverjpeg

After this you've got to find out the device name of your harddisk. You
can do this by e.g.

$ sudo fdisk -l

Once you know that your sd-card is e.g. /dev/sdc1 you can recover the
deleted pictures by

$ recoverjpeg /dev/sdb1 (1 gb nikon memory card)

result is :
Restored 732 pictures
but we did not find where the 732 pictures