It stands for GNU image manipulation program, basically an open source PS with very similar functionality for most things. Manipulating a 3d mesh is different than tweaking a 2d portrait in BG, but the principles are basically the same. Neleothesze's quick edit shows how they could take a standard human face/head and just morph it within various parameters to get a different look for the fantasy race version of that same face. I believe they have already done this for many of the heads currently available, but it is difficult to notice when they're hidden behind the cycler that only displays each face one at a time.
I think a larger selection of presets should display together as a bid grid, so showing several faces at once in a matrix. If the default is Human, then have it display say 12-36 human heads of the chosen sex. Then if the player clicks "Elf" it would show those same 12-36 heads having undergone the standard morph for Elves. Once the basic face is selected, we should have the option to exaggerate the features by pushing the morph further or dialing it back if desired, depending on whether one wants a more alien looking Elf or a more Human style one. Do the same with each race/face. Once the face is chosen, the same sort of display should work with other major selections like hairstyle. So instead of clicking 36 times to cycle through each hairstyle, you'd see your chosen face with 36 haircuts shown all at once. Pick the one you like and then it zooms back in to do all the cosmetic and color change type stuff.
ps. also when I say 12-36 heads, I mean show that many heads at a go and cycle that way - in pages rather than 1 by 1 or selecting from a list. I actually think they need at least 100 preset heads for each sex to properly execute that sort of design, but if they did it they'd have a really solid scheme to build off of.
A big part of such a presentation would be to show off the actual extent of the work, rather than hiding it behind the cycling. The cycler may create the illusion of more variety, but it's just a time sink and an impediment to the player quickly finding what they actually want out of what's available. With a survey view the player can see what's there at a glance. Doing it in a head matrix would be a simple way to showcase the variety and make it easier to see where there are gaps to fill in.
The morph to different fantasy race would have a sort of vfx movie-magic appeal too. Sort of like you're seeing the faces after the prosthetic makeup was all in place. Once you got what you want, zoom back in to selection to noodle around with the cosmetics and such. Again doing that in a grid view wherever possible. If there are 12 eye colors or 12 lip shade colors or whatever, let us see them all together at a glance. What I want from a character creator is just that, a way to present the many options in a visual overview. Basically a case of heads to choose from, like Mombi. I think it would just be a lot more efficient, while looking cooler at the same time.