@Baron:
Does B-17 rather able to do same things than B-25 but at longer range with more payload ?
I read that some of these B-17 were based in Australia and succeed at attacking a few IJN ships?
Yes and no… you’re kinda talking the difference between a tactical bomber (like the B-25) and a strategic bomber (like the B-17). The B-17 has longer range and a bigger payload than the B-25, but its also less maneuverable, and usually used for different roles (strategic over tactical bombing).
As with anything in war, there can be fuzzy lines that are crossed (B-17s used for tactical missions like bombing ships and B-25s used for strategic bombing, like the Doolittle raid), but generally speaking those two bombers were used for different purposes.