Zero Assumption Recovery (X) (ZAR or ZAR X for short) is currently the only best data recovery solution (with the most accurate data scan and recovery capabilities) for FAT, NTFS, EXT, and XFS filesystems. It was developed by Alexey V. Gubin from Russia, and enjoys a pretty good reputation and popularity around the world on data recovery field. It seems to have been specifically designed for recovering digital photos from digital devices at first, which has exposed as a free feature now (camera compatibility list for photo recovery).
On hard disk, when you delete some folders, files or even an entire partition, all data is still existing in the same place where it was, and will always be there until overwritten. In fact, the deleting operation is just delete the pointer to the data on disk from MFT (Master File Table), so as to allow the operating system to perform writing operation there. Any data recovery software use this principle to work. Of course, you can delete the data truly and completely. But that requires you to ask special data eraser for help.