Unwanted microsoft and other icon images display radomly in screen saver slide show. Unable to delete of find these files.

My home built computer running Windows 7 64 bit, Outlook Hotmail, Windows Media Center, Windows Live Photo Gallery. The unattended computer will toggle to a "Scan Dump" photo file of 1500 family photos but among these are dozens of fragmentary images of what look like Microsoft arrow keys, blank squares and other annoying images. What is really annoying it the so called selection protocol seems to prefer these over my family history. I assume these files are hidden and occasionally one or two has popped up but I`m not clear as to what I did or what the result was.

Please advise.