Isabelle Graham is accused of sleeping with a 17-year-old pupil in a city centre Travelodge and faces being kicked out of the profession.
The hearing in Edinburgh was shown a photograph of the room which apparently showed Mrs Graham in bed and the pupil near the door.
Mrs Graham, who was not present or represented at he hearing, denies the charges and claims to have no recollection of events after 10.30pm, having drunk four glass of wine.
The General Teaching Council for Scotland (GTCS) accuses Mrs Graham of going with the boy from an upmarket Edinburgh hotel where the prom took place in June 2014 to a nearby Travelodge.
The former teacher at Whitburn Academy, West Lothian, is alleged to have spent three hours alone with the teenager, drinking with him, sharing a bed with him and “repeatedly engaged in sexual activity” with him.
The disciplinary panel heard from Fraser Thomson, a council employee who investigated the case.
Mr Thomson said that the investigation began senior teaching staff were made aware that “a photograph had been uploaded on social media”.
Describing the photo presented to staff, he said: “The pupil standing in the door is Pupil A.
“You can see there what appears to be a lady in the bed there.
“The colour of the picture showed the lady with long blonde hair.”
The photo was taken by another pupil who was meant to be sharing a room with Pupil A but returned numerous times to find the teacher in the room.
Mr Thomson said evidence from students outlined how they saw “Pupil A and Mrs Graham lying on the bed, one on top of the covers and one underneath the covers”.
In an interview between himself and Mrs Graham, Mr Thomson said she claimed “she was unable to recall events after 10.30pm” because she had drunk four glasses of wine.
She claimed that her first recollection after 10.30pm was “when she woke up in her flat at about 5.00am”.
She also admitted that four glasses of wine would not normally intoxicate her to that level, and said of the hair in the photograph: “It looks like my hair.”
But she denied recognising the young man in the photograph.
NMC case presenter Carla Roth said that Mrs Graham’s claim that she was “totally out of it” as a result of her drinking “differs from comment made by any witness”.
The allegations sparked a police investigation at the time - but no charges were brought.
The main hearing followed a procedural hearing on July 26 in which Ms Graham applied to have the hearing held in private.
The attempt was denied by the GTCS on the basis that it is in the interests of all involved “that justice is seen to be done”.
Mrs Graham - who now lives abroad - did not appear at the hearing, despite being offered a videolink service.
The charges levelled against Ms Graham in full read: “On 5 June or 6 June 2014 or overnight, whilst employed as a teacher at Whitburn Academy and following the school’s Sixth Year Prom at Carlton Highland Hotel, North Bridge, Edinburgh, you did accompany Pupil A and other pupils to the Travelodge, Waterloo Place, Edinburgh, where you did have inappropriate contact with Pupil A.”
“You did spend approximately three hours alone with Pupil A in an hotel room. Share an alcoholic drink with Pupil A (age 17 at the time). Share a bed with Pupil A. Repeatedly engage in sexual activity with Pupil A.
“And in light of the above it is alleged that your fitness to teach is impaired.”
Ms Graham resigned from her position at Whitburn Academy after the alleged incident took place.
A spokesman for West Lothian Council said: “Ms Graham is no longer employed by West Lothian Council and it would not be appropriate to comment further.”