Well tried to do custom images, and manual is a bit unclear. It would be nice way to export some current character as image reference. So I would not have to guess what traits how to name. This is out of easy if editor is too much to make.
Also I assume extraReqs are those that required for image even used.
but extraPrefs part is confusing what makes it different from tags used outside like skincolour, strength and such. Like Extra prefs is similarity check, to to find closest image to the current stats, but what are floating in main numbers. I would assume it is appearance values but strength is a trait so not fit.
Also are images can only take existing traits or you can do cast there self image values, because if yes syntax would be a bit confusing. I assume it is not the case because there was no need for this.