That B-17 appears to be less than 2000 feet above the ground and probably going quite slow when the crew was bailing out and immediately opening their parachutes. The two engines on the right wing may be shut down, but I don't see any fire or apparent structural damage to the aircraft. But the crew is jumping for some good reason. If the crew had bailed out at 20,000 or 30,000 feet, they would (in accordance with their training) have done a free fall down to about 10,000 feet. That would get them down fast to an altitude where they didn't need supplemental oxygen and the temperature was usually quite a bit warmer. And the crew members would definitely remember the bone rattling shock when they did open their parachutes after that free fall.
Cooper jumped at night and when the airliner was above an overcast and several cloud layers. He would probably not be able to see any lights on the ground until he was below the clouds and he was probably tumbling at that point anyway.
I didn't mean for a single photograph to be definitive. As someone with no jumping experience, my inclination if I was put in Cooper's shoes would be to pull that ripcord as soon as I cleared the aircraft. I wish there was an easily referenced collection of WWII bailout anecdotes to be sure, but my gut instinct is most of those guys weren't interested in freefalling. Regardless, until someone collects all those anecdotes, it's speculation.
Here is the case I would present for a Cooper "early pull" (not "squidding"):
-He wanted the stairs down on takeoff, signifying he wanted to jump soon after takeoff
-He was trying to jump before the plane had finished its ascent to 10,000ft, and was only delayed by his unfamiliarity with the airstairs and how they deployed in flight.
So, if he wanted off that aircraft as it was ascending, then he was not planning on a lot of free fall and was more likely to pull early.