This is a riddle?
What is the logic of the sentences on the right that leads to the actions required to get a correct number?

What in the riddle leads one to choose the 2 numbers after the words? As opposed to the numbers before the words, or the numbers bracketing the words. A riddle should not devolve into a trial and error exercise. Perhaps a "xxxxnn" logo at the bottom of the page.

The height of an object in a photograph depends on the distance the object is from the camera and how the camera is focused. Assuming the "scale" in one photograph can be applied to another photo makes no sense.