The short answer is yes. You can't harm a cast iron Dutch oven with the temperatures generated by a normal campfire.
Ideally you have the type of Dutch oven with three legs and a lid designed to hold coals. Those were specifically designed to be right in the fire.
The more common type with a flat bottom and domed lid are probably better used by suspending with their bail instead, simply because they're more prone to burning the food when in direct contact with the coals. However, you can cook perfectly good meals with them by learning how to let the fire die down into nice cooking coals, and how to bank the coals for effective cooking (more like your second diagram).
I have both types and prefer cooking on my three legged oven. My brother prefers the flat bottomed kind, but he's got the tripod for suspending the oven, and I don't.