I suppose it happened almost everybody to have some digital photo accidentally deleted from a memory card. It happened to me some days ago, after a power failure, I discovered the photos I was moving from the camera already had disappeared from the memory card but never had been saved on the hard disk.
The undelete process
The memory card, fortunately, did no suffer any damage during the power failure. Following instructions on this Ubuntu community documentation page I installed foremost:
sudo apt-get install foremost
then I executed it
sudo foremost -i /dev/sdc1 -o /recovery/foremost
“/dev/sdc1” is the card reader device .
The program extracted all previously deleted in the output directory all neatly separated, by file type, in different folders.