The Alt-F10 option to grab high res game images only works in non-Open modes... Why exclude Open from this feature?
It's not that it doesn't work in open, it's that it only works in solo (ie it doesn't work in PG either). It's because the game micro-stutters as it creates a giant screenshot and it could be used to gain an unfair advantage in PvP by forcing your ship to rubberband.
Hi res screenshots stall the game briefly and suspends network traffic. That can lead to a dsync exploit.