Why are my photos blank (Windows Vista)?

I just imported some photos onto my computer today. I could see the photos fine. Then I proceeded to edit my photos in Microsoft Office Picture Manager. I was also running a Norton 360 scan at the same time. When my Norton scan ended, some of my photos were showing up blank/white. I closed Picture Manager without saving and went to see if my photo thumbnails were showing up in my Photos folder. They were still blank so I restarted my computer in hopes of it fixing itself. When my computer restarted, the photos were still coming up blank. I really need these photos and would like to recover them. The files are still there, they just look like I took a picture of a white abyss. My Norton 360 scan cleaned up Windows Temporary Files, and I believe this may have to do with why my photos messed up. Please help.