That is the first piece of concept art that has emerged for Half-Life 2: Episode 3 and it will be part of the Into The Pixel exhibit for the E for All Expo later this year. The piece appears to show a Combine Advisor floating above a figure which is most likely Gordon Freeman in the possible ruins of the Citadel from City 17.

Valve have already stated that Episode 3 won’t be present at E3, will we see more of it at the E for All Expo in September though, who knows?

thanks to CVG