Mommieof2 - you can do a similar thing with privacy setting on myspace photos. I only have my friends allowed to view my page at all - or my photos. You can also set the photos so that only YOU can see them. I know some people who do this and then tell a couple people, "hey, I'm going to open up the pics of my kid for two days and then private them again" - even then, the only people that can see the pics are "friends" that you approve.
Cupcake's Mom told me I could do what I wanted with Cupcake's pictures since she trusts me with them. She wants me to be able to show Cupcake off and brag about her to my friends. In today's world, on the internet is one of the easiest/best ways to do that.
I have taken every privacy precaution and I gaurantee you no one can crack into my myspace without my say so. My Myspace is so hard to find that I've told people on here to find me there to be "friends" and they can't even find me when I tell them too!
If you want to be able to share the pics with your childs firstmom, and want her to be able to share them with people in her life, I would talk to her about your concerns re: privacy and lay what you think are appropriate boundaries.