The picture in chapter 23 is Kharsh.
There are drawings of many of the characters...only a few actually appear in the books right now. They are: Gaelen (who seems to be everywhere), Fima, Nelwyn, Galador, Azori, El-morah, and some of the horses. We see a picture of Rain, and several of Shandor. There's one of Duinar (and a character you haven't met yet) in you-know-what.
Why them and not Gorgon? Because Gorgon is unique. The mental picture you have of Galador isn't likely to be very far afield from my drawing of him, but the villain, who is a unique creature (to say the least) might vary widely between readers. I don't want to mess with your vision.
I have Paintings of Shandor and Kotos and Dardis here at home. Also several of Gorgon.