Wendy,
You've got a great business model and you (and your husband) have integrated the web perfectly into your business. The people you've got coming to your site are *highly* motivated - nobody can pass up a chance to see a picture of themselves (or more importantly, their kids
), but I question if these people will necessarily have any interest in the "field" of photography...this site may not be the best vehicle to do affiliate marketing.
Even if you put up some Adsense ads, the context of the site will cause the ads to be geared toward photography - until you test it, you can't be sure that this "stream of traffic" wants to do anything but look at photos - not neccessarily take them.
The other concern to consider is the possibility of *confusing* your visitors on the purpose of the site. I'm a strong believer in a *one theme* website - forking off into different directions may hurt your primary business.
My .02 - I'd be curious what others have to say on this topic...