I have a Sony HDX-550V. Every time I download video to my Windows 7 desktop machine, I get the same group of unwanted still images. These images were apparently taken inadvertently at some time in the past while filming video. The images do not show up on the camcorder when viewing still images. Thus, they do not seem to be normal protected images. I tried to get rid of them via the protection function and could not find them. Any ideas?