"When I was looking in the Book of Shadows, I saw these woodcarvings. They looked like something out of a bosch painting. All these terrifying images of these three women battling different incarnations of evil."
The woodcarving of the Three Witches was only seen from a clear angle during the Unaired Pilot. It can be seen in "Witch Trial" for a split second, however, it's from a bad angle.
In the season 1 episode The Truth is Out There... and It Hurts, Tanya Parker is looking in the Book of Shadows. She is flicking through some of its pages, which all show woodcuts. If you look closely, you'll notice that it's not the Book of Shadows, but just a regular book with woodcuts in it.
The Trading Cards of season 1 had a special Book of Shadows line, in which several spells from that season could be collected. Next to those spells would be woodcut. Only one of them was in the actual Book of Shadows; The woodcut of the Three Witches.