I have read the tutorial over and over. It is not clear and does not outline what you are referring to for an image. In fact, it does not refer to anything special for an image.
I do see where it talks about Original field data and Raw data, but doesn't really say which one to use for images. I do apologize.
And apparently, I failed, I went to the tutorial and copied from the tutorial instead of copying what you indicated. Over-site and I do apologize.
So, I tested what you are saying, here are the results:
{cb}[cb:userfield field="avatar" user="846" /]{/cb}
Works great.
Thanks again for putting up with my dumbness... haah