[Armin can't see Kate's face, but he recognizes the confusion - the awe, even - all the same.]

It's called a photograph. Have you seen one before? [He assumes not - she can correct him if he's wrong.]

A device called a camera is pointed at a subject - like the people in this photograph. [Is one Kate? Surely, the blonde girl with the ribbons in her hair must be. Or...maybe it's just coincidence, another trick.] The device creates a flash of light, which burns the image of the subject onto a special type of paper called film. You develop the film to create a full-sized image like this one.

It's all science, but when I was young, I didn't know what they were either. It's kind of amazing, isn't it?

[As for why this photo is here...

[He frowns just a bit.]

I couldn't tell you how they got a photo of the place that you came from, but...

There are a lot of things I don't yet understand about this place.