Open Control Panel, click on the View tab.
Check Show hidden files, folders and drives.
Uncheck Hide empty drives in the Computer folder.
Uncheck Hide extensions for known file types.
Uncheck Hide protected operating system files (Recommended).
Open a Command Prompt.
Type dir pictures and press Enter.
See if any picture files (jpg/gif/png/bmp) are in there that are not pictures you expect to be there.
When you're done, go back and check Hide protected operating system files (Recommended). You can also check any of the others you want.