I see a lot of ban request topics without screenshots because people cant get it to launch from steam anymore, as they are used to the F12 hotkey to save screenshots in steam.
Simply put, holding down ctrl and pressing insert will save it to your computer, it will show in the chat log where the screenshot is saved. This is a warband shortcut and does not rely on any third party program to save the screenshot for them.
Just throwing that out there for those who did not know