Fans noticed that as they watched the movies, some of the pictures for news articles would move while others did not, and this baffled people for years until one Reddit post gave a clue as to why that would be the case.

Why don’t all of the photos move in Harry Potter’s ‘The Daily Prophet’?

Harry Potter fans on Reddit theorize that some pictures don’t move because they were taken by muggles. RELATED: Harry Potter Stars Will ‘Return To Hogwarts’ Without JK Rowling For 20th Reunion Special “In Harry Potter and the Deathly Hallows Part 1 (2010),” reads the title of the post, “the photo of the muggle family in the newspaper isn’t moving like the rest of the photos in that paper. This is because that photo was taken with a muggle camera.” The headline for the article was “Violence Spreads: Muggle Family Murdered,” and features a photo of the muggle family — a mother, a father and a child in each of their arms. According to the user who made the post, the photos don’t move because they were taken by muggles, but a response to that post quickly disproved that this wasn’t actually the case. “Except it’s explained in the books that you can process a muggle-camera-taken photo to move,” wrote the reply, linking to a Harry Potter wiki. The link leads to a page about a potion called “Developing Solution” which was introduced in Chamber of Secrets during Chapter 6.

Not only that, but J.K. Rowling has answered questions about this on her official website.

So theoretically, they could have used this potion to make that photo come to life, similar to the Live Photos feature on the iPhone. RELATED: J.K. Rowling Shares Another Anti-Trans Tweet As Study States She Is Causing ‘Damage’ To LGBTQ Equality The poster tries to argue that the photo in the newspaper that doesn’t move, doesn’t move because it was already developed.  “The newspaper didn’t get it from film, they got it as a developed photo,” they said, however, this isn’t specified anywhere. What is specified, is that the developing solution has to be done during the developing process. Colin Refers to Colin Creevey, a muggle-born wizard at Hogwarts who was a big fan of Harry Potter and photography. Technically, both of these Reddit users are correct. If the photo isn’t moving, that means it likely wasn’t developed using the developing solution. This could be for any number of reasons, from the muggle-developed film to stylistic choice to highlight more important stories in the paper. Whatever the case may be, some photos don’t move simply because they weren’t developed using the magical potion. RELATED: Is Emma Watson Retiring From Acting? Inside The Rumors The ‘Harry Potter’ Actress Is Leaving Hollywood Isaac Serna-Diez is a writer who focuses on entertainment and news, social justice, and politics. Follow him on Twitter here.