Portrait McGonagall

The Portrait of Minerva McGonagall is a portrait woman whose home frame hangs in Hogwarts as of 1993.

Origins
In 1954, following her tearful breakup with Dougal MacGregor, Minerva McGonagall decided to have a portrait of herself created right there and then, so that no matter what happened to her, there would always be a version of her to vividly remember her past love for Dougal. The painting was created by Oliver Cartwright and infused with a large portion of McGonagall's own memories.

1956-1992
When the true McGonagall became a Professor at Hogwarts, she brought her portrait there at her request, as the great number of Portraits there would allow her greater freedom of movement and give her more new portrait-people to meet. With then-Head of Gryffindor Professor Dumbledore's permission, McGonagall placed the frame in the Gryffindor Common Room. This allowed her portrait self, to whom she had grown quite close, to watch over the students and make sure they properly did the homework assigned to them by the flesh-and-blood McGonagall.

1992-1993
After Sirius Black broke into Hogwarts, some time after the Christmas holidays, he abducted Ron Weasley, intent on finding the whereabouts of Peter Pettigrew. Wondering where he had gone, Hermione Granger called onto the next portrait she saw — namely McGonagall — to go off and ask all the other Portrait People in the castle if they'd seen him. The Portrait McGonagall eventually found a witness of Ron's abduction, the portrait of Hengist Rawkes.

Following the recovery of Ron, Hermione began chatting with the Portrait McGonagall often, more or less becoming friends with her over the rest of the school-year.