Nobody posts SS'es anymore, but it's more for the one who asks, you can tell them all to fuck off and use /ss command.
Anyone in the game (probably including obses) can use /ss durind the game and for example 8 screenshots from all 8 players will be uploaded to the server, watch Mistral's link, there you can examine them.
So you can politely tell your opponent «Please use /ss command and fuck off»