-
Proper chain length in most cases is the shortest you can make it in big/big plus a one pair of links, yours looks like it might be a touch shorter than that but it's not so short that going big/big is pulling the mech apart and as you already know not to use that gear, and it won't explode if you do it accidentally, I wouldn't worry about it and double check it's correct when you get your next chain.
Nothing's on fire yet...
Yeah, was using big-big to illustrate the derailleur at maximum stretch.