There is a check mark...in a blue or green box...that is placed on all jpeg files. I can't get rid of it. It j?

When my computer crashed, the marks were gone when we got it up and running again. When I downloaded photos from my cannon camera they reappeared on every jpeg file everywhere on my computer. I've been trying to get rid of it, but can't. Apparently I can change icons, but not get rid of this checkbox. I can't find a forum on Cannon's website to get help.