I'm just going to go from book 1 anyway.

tEotW: Ishamael staring at his figurines
tGH: Drawing of Rand and Ishamael battling over Falme
tDR: Rand holding Callandor. Obviously.
tSR: Arrival at Rhuidean by Portal Stone
tFoH: Moiraine vs Lanfear. Actually, I'd just leave the current pic because it's awesome.
LoC: This one's hard to sum up. Maybe Egwene, Rand, Elaida and Taim on daises or something, glaring at each other, and with figures watching from the shadows. No one scene comes to mind.
aCoS: Something to do with the crown. Possibly it being placed on Rand's head considering the prophesies.
tPoD: Tough. Maybe Egwene in the Little Hall, or at the meeting with the nobles.
WH: I feel like this one should be Mat, which sadly means him sneaking around in one of his ridiculous outfits. How about I recommend this and request not to be the one to draw it. I'm quite happy not visualising that.
CoT: Perrin sitting and staring at his hands
KoD: Maybe Elayne standing on the wall.
tGS: Dark Rand looking emo anything but that.