Where episode is this pic from?

That picture is from the first "regular" episode of the series titled "Mork Moves In" , following the pilot episode. Hope this helps.

Yep.
After Mindy and her dad have a fight, Mork decides to leave so as not to destroy the father/daughter relationship. To celebrate him moving on with his new life, Mindy gives Mork ginger ale. Unbeknown to Mindy, Orkans get "bezurbed" or "ork-faced" when carbonation hits their bloodstream.