1. Download, install and use Smart Image Recovery 2.3 if you need to recover images after reformatting the memory card or overwriting some of the erased files. This program scans your memory card to find lost images ending in .jpg, .gif and .png, three common photo file extensions. Smart Image Recovery 2.3 will also work on your hard disk (if you accidentally delete photo images from it), and it supports Windows NT, Vista and 7 operating systems.

2. Try Zero Assumption Digital Image Recovery 8.4 (ZAR) if you want to recover deleted images from CompactFlash, MemoryStick, SmartMedia or other memory devices. ZAR recovers digital photos, video and sound files in the following formats: GIF, JPEG, TIFF, CRW, MOV, AVI, WAV, CR2 and ORF. Once you download and install the program, plug in your camera or insert your memory card into the card reader on your computer. The program will walk you through the steps to find and restore your deleted images. After ZAR finds the images, you have the option to select the ones you want to recover and to choose a directory to put the recovered files in.

3. Download MjM Free Photo Recovery Software to recover accidentally deleted images. Once you install this program, it automatically detects your media card--once you place it in your computer's card reader--and begins its search for deleted images. View the thumbnail images of the pictures the program finds, and then choose the ones you want to recover (or choose all). Use MjM Free Photo Recovery Software with CompactFlash, Memory Sticks, SmartMedia and other types of memory storage cards your camera may use. You cannot use this program for images deleted from your computer's hard drive. One option for "deep scanning" takes a long time (hours, depending on the storage capacity of your memory card), but will locate many deleted images, even those that have been written over or on cards that have been reformatted.

Here's how (all are freeware):

http://youtu.be/YnC047mRuNU