Grandma accidentally deleted her photos from her camera SD card. Here is how I recovered them using a free GNU license software called PhotoRec. See http://www.cgsecurity.org/wiki/PhotoRec for details on the software.
* Download TestDisk from http://www.cgsecurity.org/wiki/TestDisk_Download. I downloaded Windows 32bit version.
* Unzip to a local directory, e.g. c:\prog.
* Double click photorec_win to start the program