Suffering from Corrupted Images

At some point in January I loaded precious photos of my Little Man from the camera SIM card to my external hard drive. When I went to click on the newly loaded images though they all looked like this:

I have NO idea why this happened and the worst part? It's happened again! All the photos I took for January, February and the few I've taken so far in March are ruined! I am quite upset as there are some irreplaceable photos of LM with his great-grandma and other people. Not only have I probably lost all those photos, but I can't use any of the photos for blog posts I had written up either! This is SO frustrating!!!

I cried over this before and I'm crying over it now. I really have no clue what to do about it. I'm not sure why or how it's happening and as of right now I can't find any way to recover the photos that are messed up. Any ideas or help would be great!