You don’t need to be three-dimensional to be full of life inside the walls of Hogwarts.

Hogwarts, like any self-respecting old building, is full of works of art. They adorn the stairwells and line the walls of the Headmaster’s office – gilt-framed and larger than life.

The most convincing examples of the artistic school of realism ever, Hogwarts portraits are imbued with the memories and emotions of their subjects: they sidle between frames and interact with the living, spending their time drinking, singing, shouting and generally seeming to have a better time with their legs painted on than we’ve ever managed in real life.

In the Muggle world, portraits are often as much about the artists as they are about the subjects; in the wizarding world it’s all about those portrayed in paint.

These are the portraits with the biggest influence on the action:

The Fat Lady

The Fat Lady, clad in a floor-length gown, and charged with the important task of guarding the door to the Gryffindor common room, leads a life of decadence and delight. Alternately depicted singing, necking whole casks of wine and socialising with her posse, she knows the value of a liqueur chocolate and a tinsel headband.

She might be a fan of the finer things in life, but she suffers at the hands of Sirius Black, when she refuses him admission to the common room. Two parts sarcasm and one-part whiskey, she’s the portrait with the most staying power, making regular appearances throughout the novels, always equipped with top-notch passwords such as ‘banana fritters’, ‘baubles’ and (after some festive over-indulgence) ‘abstinence’.

Of all the animated oil paint, she’s the most human. She celebrates wins with the Gryffindors; she mourns Dumbledore’s death. And since the levels of activity of the portrait is a direct reflection of the powers of the witch or wizard in life, we’re sad we never got to know her in the flesh. She’d have really enjoyed the Three Broomsticks.

‘I’ve got something for you, Harry,’ said Hermione, neither looking at Ron nor giving any sign that she had heard him. ‘Oh, hang on – password. Abstinence.’ ‘Precisely,’ said the Fat Lady in a feeble voice, and swung forwards to reveal the portrait hole. ‘What’s up with her?’ asked Harry. ‘Overindulged over Christmas, apparently,’ said Hermione, rolling her eyes as she led the way into the packed common room. ‘She and her friend Violet drank their way through all the wine in that picture of drunk monks down by the Charms corridor. Anyway…’
Harry Potter and the Half-Blood Prince

Sir Cadogan

This portly knight makes his first appearance in Harry Potter and the Prisoner of Azkaban, when he aids Harry and Ron in finding their first Divination class. Though he’s clearly committed to his knightly duty to aid those in need, he’s not exactly what you would call competent. All over-long sword and grass-stained knees, he spends more time trying to get back on his pony than he does rescuing damsels in distress.

Still, you can’t say that he’s not brave: when the Fat Lady’s canvas is slashed to strips by one knife-happy Sirius Black, it’s his portrait that takes her place guarding the Gryffindor common room, with its precious Harry-shaped cargo (leaving aside the fact that he subsequently cheerfully admits Sirius through, when he comes equipped with Neville’s list of passwords).

Cadogan’s last appearance is during The Battle of Hogwarts, when he accompanies Harry on a mad dash through the corridors, shouting encouragement, ready for battle to the last.

‘Farewell!’ cried the knight, popping his head into a painting of some sinister-looking monks. ‘Farewell, my comrades-in-arms! If ever you have need of noble heart and steely sinew, call upon Sir Cadogan!’ ‘Yeah, we’ll call you,’ muttered Ron, as the knight disappeared, ‘if we ever need someone mental.’
Harry Potter and the Prisoner of Azkaban

‘Braggarts and rogues, dogs and scoundrels, drive them out, Harry Potter, see them off!’
Harry Potter and the Deathly Hallows

Ariana Dumbledore

The youngest Dumbledore is never present as a ghost, but her spirit is everywhere, haunting Albus Dumbledore throughout his life.

It makes sense, then, that it’s her portrait that provides Harry with his most pivotal return to Hogwarts, concealing the passageway between Aberforth’s house and the Room of Requirement. She’s nothing but memory, reflection, paint on canvas: an ever-present reminder of the impossibility of restoring what once was lost.

Ariana’s portrait, described as nothing more than blonde with ‘vacant sweetness’, never speaks, unlike the garrulous occupants of most of Hogwarts’ paintings. Deceased long before the events of the books, she is the silent catalyst, the unspoken regret, the family secret.

Aberforth remained fixed in his chair, gazing at Harry with the eyes that were so extraordinarily like his brother’s. At last he cleared his throat, got to his feet, walked around the little table and approached the portrait of Ariana. ‘You know what to do,’ he said. She smiled, turned and walked away, not as people in portraits usually did, out of the sides of their frames, but along what seemed to be a long tunnel painted behind her. They watched her slight figure retreating until finally she was swallowed by the darkness.
Harry Potter and the Deathly Hallows

Phineas Nigellus Black

An ex-Headmaster of Hogwarts and Slytherin to his oil-paint core, Phineas hangs in the Headmaster’s office and represents the silly side of evil. He feigns sleep when Dumbledore calls upon him, and speaks only to reinforce his intense dislike for Harry Potter, all Gryffindors, and more or less everyone without the surname Black.

He plays an important role in Harry Potter and the Order of the Phoenix, as his other painting adorns the dirty walls of 12 Grimmauld Place. He therefore serves as an unwilling messenger for the Order.

A wearer of silk gloves and admirer of style, the child-loathing ex-teacher is extremely well-endowed with personality and pride, if not with charm. He might be deliberately loathsome, but he’s also capable of words of wisdom, and his sneering disregard for Harry is what enables him to give Harry an essential talking-to when he verges on breaking down

‘You know,’ said Phineas Nigellus, even more loudly than Harry, ‘this is precisely why I loathed being a teacher! Young people are so infernally convinced that they are absolutely right about everything. Has it not occurred to you, my poor puffed-up popinjay, that there might be an excellent reason why the Headmaster of Hogwarts is not confiding every tiny detail of his plans to you? Have you never paused, while feeling hard-done-by, to note that following Dumbledore’s orders has never yet led you into harm? No. No, like all young people, you are quite sure that you alone feel and think, you alone recognise danger, you alone are the only one clever enough to realise what the Dark Lord may be planning –’ ‘He is planning something to do with me, then?’ said Harry swiftly. ‘Did I say that?’ said Phineas Nigellus, idly examining his silk gloves. ‘Now, if you will excuse me, I have better things to do than listen to adolescent agonising … good-day to you.’
Harry Potter and the Order of the Phoenix

The Provocative Mermaid

Just because she doesn’t get given a name doesn’t mean this scaled siren doesn’t play an important role among the framed alumni of Hogwarts. Given prime position in the prefect’s bathroom, the mermaid spends her time flirting with the finer prefect specimens as they wallow in their flashy swimming-pool-sized tub. While it can’t be ideal to be an aquatic creature left high and dry, she certainly knows how to make the best of her situation.

Harry’s eyes had fallen on the picture of the snoozing mermaid on the wall. ‘Myrtle, there aren’t merpeople in there, are there?’ ‘Oooh, very good,’ she said, her thick glasses twinkling. ‘It took Diggory much longer than that! And that was with her awake, too – Myrtle jerked her head towards the mermaid with an expression of great dislike on her glum face – ‘giggling and showing off and flashing her fins...’
Harry Potter and the Goblet of Fire

Violet

Best pal to the Fat Lady, Violet doesn’t seem to do much more with her second life than imbibe fine wine and indulge in lengthy gossip sessions with her friend. An icon to us all.

‘Well, well, well,’ said the Fat Lady, ‘Violet’s just told me everything. Who’s just been chosen as school champion, then?’ ‘Balderdash,’ said Harry dully. ‘It most certainly isn’t!’ said the pale witch indignantly. ‘ No, no, Vi, it’s the password,’ said the Fat Lady soothingly, and she swung forwards on her hinges to let Harry into the common room.
Harry Potter and the Goblet of Fire

Cumulatively, the canvas occupants of Hogwarts play a key role in events that transpire, from protection to betrayal – human to the end. I hope that any future portraits capture McGonagall’s raised-eyebrow wrath, Sirius’ sardonic humour and Harry’s bravery. It’s reassuring to know that there are multiple ways that our favourites might live on in death, whether it be as portrait or ghost, or both.