Sending a dot.mac invite for a online slide show

OK, I've figured most of this out, but one thing I was wondering about was are there any sort of variable preferences that you can change or do different machines interpret what a mac sends? I did my first invite yesterday, and my buddy with a mac got his with a thumbnail view, and my daughter got hers with a carousel view. I was hoping that I could make sure that everyone got the carousel mode version.

Is it possible that my buddy with the mac has some sort of preferences set on his machine that switched it?