Don't want to rain on your parade, but we are going to need a few other things ...
1. Socks - significant variation in thickness and of course we need accurate weight measurements as well to judge both the sock and shoe compressions per kilogram.
2. While I am sure the pavers tried to make the area they are standing relatively flat, I would expect they also have planned for drainage and therefore the surface they are standing on will have some slope in the direction of the nearest sewer grate. We need volunteers to do a proper site survey.
3. Looking at the background it would also appear that the photographer was not using a self leveling tripod and the camera was not in fact level at the instant of exposure. Perhaps our math/engineering members could work out the calculation to determine the distortion per foot of distance from the camera to the subjects.
This is not as simple an issue as your truly naive plan to simply measure footwear! Hmmph! This is the reason we keep having these disputes, people trying to cut corners!
