I call BS on just a timing belt breaking. Those pistons and chambers look like they've been melted, like there was a horrible lean condition for a while under high load. Valves don't break holes in all four pistons when the belt snaps, the valvetrain stops rotating long before that kind of carnage happens. Plus, the piston holes wouldn't have melted edges on them, they'd just be a clean fracture and nothing else (the valvetrain wouldn't have any more energy left after a few good piston hits and it isn't getting driven with a broken belt).
That's a LOT more damage than the engine shutting off at 40MPH because of a broken belt. I see the bent/broken valves, but that belt must have jumped a few teeth a long time before it actually broke in order to blow holes in the piston tops..

Where did that picture come from? What's the real story behind it?