
Interesting thought I had about the existence of photography in the Shrek universe
You don't need to invoke magic to believe that a medieval society like Shrek's could have invented the polaroid style camera that Shrek and Donkey use in the first film. The camera obscura has been known since 400 BC; the problem was finding a way to preserve the image. In our timeline, it took until the 19^th century to do that, via chemicals that change when exposed to light. But it's entirely conceivable that a medieval society with an advanced knowledge of chemistry could have found the right combination of chemicals a lot earlier than we did.
And Shrek's civilization does have advanced knowledge of chemistry. We see a whole potion factory (chemical plant) in Shrek 2.