Just like how you reply back click on the red "selecting them" and it will upload your screen shots of your battles you have on your computer or device and don't forget to go to your battle log and copy and paste your battle link along with the upload photos like this!
https://splinterlands.com?p=battle&id=sl_0e0b3bcbfd46ca75be631b1dee79ff75&ref=frankcapital