Not 100% sure, but that looks like the lagoon at Ko Phi Phi. If you are standing there and can see the wave coming it is a long way to high ground. From what I remember there is some high ground on either end of the island with the middle being quite low and only hundreds of yards across.
Those pictures were posted on another thread saying the family made it. It turns out the pictures were taken at Krabi, not Ko Phi Phi.