how do I replace a photo?

2:40 P.M. on 4-30-14

https://www.nkscouting.com has a photo of myself in a blue/white shirt. If you click on “read more” under the title “About NKScouting,” you’ll see a photo of me wearing a red shirt.
How could I get that photo, the one of me wearing the red shirt, to replace the one of me wearing the blue/white shirt, so that both photos would be the one of me wearing the red shirt? I’ve posted this before, and no one answered!

Thanks!