I recently was being "smart alec" and thought I would delete duplicate pictures on my computer. Turns out I deleted a bunch of stuff my picture software (creative memories memory manager) needed in order to view the pictures properly. When you open the software you can see all my pictures (thumbnail view) but when you click on them to see the full size picture all you see is a blocky picture which is nothing more than the thumbnail blown up. Can you have deleted the fullsize picture but have kept the thumbnail? I was able to retrieve some of pictures using a software program called "Digital Photo Recovery" but not all of them. Just wondering if this is now a LOST cause or what!! Yes. Depending upon how your THUMBNAILS were created you can most certainly delete the fullsize image while maintaining the thumbnail image. Often a program that creates thumbnails will copy the image and resize it to generate the thumbnail.

Unfortunately UNLESS you've got them backed up if the image recovery program you've used to attempt to recover the images cannot recover certain images it's likely that they've been overwritten.

Over time files that are marked as deleted on your HARD DRIVE will be overwritten by new data, making it impossible to recover the data that was overwritten.