The Old African by Julius Lester
Though long for a picture book, the illustrations are so stunning and so integral to the work, that it meets the criteria of a picture book. The old African was captured by slave traders as a young man, but he possessed power that grew in his years of slavery. He learned to shield others from pain, he could see into the minds of others, even if they were far from him, and he could bring storms. Finally, he leads other slaves on the floor of the sea to freedom in Africa. The story and illustrations work together to tell a story that is both beautiful and haunting.