Someone just sent me this image:
And, this one is viral on Facebook and Google+:
Are they from an actual TV episode, or are they Photoshopped images?
Real episode. This happened in the episode "Phantasms" (Star Trek: The Next Generation).
In engineering, Data sees dream imagery while he's awake. He sees a 'mouth' on Geordi's neck, and the engineering tool he holds looks like the knife with which he cut the 'cellular-peptide cake'. He hears the telephone ringing again and Riker appears with a straw in his head, ordering Data to "answer it". Data opens his own chest and picks up the telephone receiver.