Hi,
I would like to create a character customization screen similar to a simplified version of this :
https://oldschool.runescape.wiki/images/thumb/e/e4/Player_customisation_interface.png/220px-Player_customisation_interface.png?48229
Where you can change attributes (in my case race, gender, skin colour, hair, height etc) and the game will show a corresponding image according to the combination.
Is this even possible?
Thanks

It's possible.

The simple version is to just have a bunch of Show Menus ask "What hair color do you have?" and then you choose from a String List filled with available hair colors, then set an attribute Player.HairColor to the result. No image.

Now, showing the image. That IS possible, but OUTLANDISHLY difficult. With Quest's interface, short of some SERIOUS Javascript magic, the only way I can see you doing this is by creating a picture for every single possibility and having the game show the corresponding image.

Now, showing the image. That IS possible, but OUTLANDISHLY difficult.

Difficult, yes, but not OUTLANDISHLY difficult. These pages may get you started. Some knowledge of HTML, CSS and possibly JavaScript will very much help.

http://docs.textadventures.co.uk/quest/ui-dialogue.html
http://docs.textadventures.co.uk/quest/ui-dialogue-points.html