Face Unlock will not work with a picture", Google

Google has launched IceCream Sandwich with new face unlock feature which makes it interesting. I have not used it so can not say more about the feature.
But The Cyanogen lead developer Koush tweeted that we can hack into other phone by using his/her picture to fool this feature. Is it possible? Every one wants to know. But Google engineers have refused all the possibilities for hack using pictures.
Now we can wait for the feature to com on our phone.