Where and how is there an electric light at Hogwarts?

Question

The chapter illustration for Chapter Twelve of Chamber of Secrets shows Harry examining himself in a mirror after using the Polyjuice potion to transform into Goyle. Interestingly, the light above the mirror seems to be some sort of electric light/lamp.

The description of (what is apparently) this scene in the book doesn’t mention the light source:

Harry unlocked his door and stepped in front of the cracked mirror. Goyle stared back at him out of dull, deepset eyes. Harry scratched his ear. So did Goyle.

However, back in Chapter Nine the bathroom is described in more detail:

It was the gloomiest, most depressing bathroom Harry had ever set foot in. Under a large, cracked, and spotted mirror were a row of chipped sinks. The floor was damp and reflected the dull light given off by the stubs of a few candles, burning low in their holders; the wooden doors to the stalls were flaking and scratched and one of them was dangling off its hinges.

It thus seems that the light source in the bathroom was candles. Indeed, throughout the series there are many references to candles and torches as the lighting system in Hogwarts. I don’t believe there are any references to electric lights.

More importantly, we know from Chapter Twenty-Eight of Goblet of Fire that electricity doesn’t even work properly at Hogwarts:

“All those substitutes for magic Muggles use — electricity, computers, and radar, and all those things — they all go haywire around Hogwarts, there’s too much magic in the air. No, Rita’s using magic to eavesdrop, she must be.... If I could just find out what it is... ooh, if it’s illegal, I’ll have her...”

In light of the above, how can this illustration be explained?

Answer 1

All I can assume is that there was, as you appear to have discovered, an inconsistency, at least between the text and the illustration. It isn't uncommon, from what I've heard, for illustrations to not match the stories that go along with them - look at the original covers for the Ender's Game series for a chief example of this. They have zero to do with the books.

Answer 2

As you can see from Harry Potter Hogwarts Mystery (Year 7, Chapter 3) Muggle inventions that are electrically powered (including lightbulbs) can be made to work at Hogwarts. We can reasonably assume that magic is used in place of electricity since we know that electricity doesn't work there.

Today we will review the many marvellous Muggle inventions that we use in the magical world. From light bulbs to radios, Muggle inventions have made their way into the wizarding world.

As JKR said on her original site, many Muggle inventions can be made to run off the 'magical atmosphere'. There's no good reason to assume that bulbs aren't the same.

Why did Colin Creevey's camera work etc?
Cameras, like radios (or, as the wizards call them 'wirelesses' – they're always a bit behind the times when it comes to Muggle technology) do exist in the wizarding world (there's a radio in the Weasleys' kitchen and we know there are cameras because of the moving photographs you see everywhere). Wizards do not need electricity to make these things work; they function by magic, but in the case of such objects the wizards liked the Muggle invention enough to appropriate the idea without adding cumbersome plugs/batteries.

SO... as Colin's batteries can't work in Hogwarts, clearly his camera is running off the magical atmosphere

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