Neal: I would say that the tires you have pictured, with all those cracks in the surface rubber, need to be replaced regardless of age or mileage or tread.
When water gets into the steel belts the latter will rust. Not long after the steel will rust through and the tire is now liable to have a blowout.
When water gets into the steel belts the latter will rust. Not long after the steel will rust through and the tire is now liable to have a blowout.