Triple monitor surround desktop wallpaper?

Hey i have 3 screens right but im new to this and i want to know how to have 1 picture span the whole 3 scrreens. Yes the picture is big enough its 5120x by 1080

set it as the background..... I think....

Well there are several ways you could do this, one is to just split the picture in photo editing software, but I would recomend downloading software such as Actual Multiple Monitors, with more options for multiple monitors.