Oldgrape, those pics are of very severe cases. But what you describe definitely sounds like oral thrush to me. It's a fungal infection called candida. It's nothing to be too worried about as it's quite common and easily treated but it will make his little mouth feel sore. Take your little one to the doc asap and they will be able to give you something to treat it, most likely nystatin in the form of Nystan Oral Suspension. It comes in a dropper bottle so you just have to drip it into your little one's mouth. It does ftakes a little while to clear though.