I've been playing with this a bit...I printed the side-by-side out and marked and measured the facial features. The length of the nose and the earlobes may change over life, enlarging a bit, but features such as distance between the eyes and ear, and length of the upper lip (called the philtrum

) do not.
The second photo looks like it has been enlarged to match the first, so it's not as distinct. Anyway, I was looking for a ratio, not raw numbers, because if you measure a large photo against a small photo you won't get the same numbers even if it's the same person. However, it seems I don't even have to work out a ratio because the heads in both photos seem to be exactly the same size.
So here are some numbers for you, raw. You can draw your own conclusions, everybody

Feature: Photo # 1 Photo #2
Distance from pupil to pupil: 15mm 16mm
Width of mouth: 11mm 11mm
Length of nose
(from line drawn between
pupils to end of nose): 10mm 11mm
Nose to chin (from came line): 25mm 25mm
Length of philtrum: 7mm 6mm
Distance between tops of ear arch: 37mm 37mm
Over to you

Cheers,
China