Yes content is King and king is the only one in the palace. There is lot of queen in the kings palace, they include, keyword, traffic, meta tag, backlink and lot more.
king(Content) and queen(seo) had a good palace (Layout design). So many people came to watch them (traffic). Money flows auotmatically...
If content is the king, then the image with the content is the queen . Definitely, images increase the value of content! Content without any image seems like a king without a queen .