In most cases the longer axle end goes on the sprocket side.
The two cups presumably have opposite threading, one "right-handed" (normal) and one "left-handed" (backwards). The right-handed ("normal") cup goes on the left side, and the left-handed cup goes on the right side.
With some BBs, both cups are "adjustable", to allow the shaft to be moved left or right a few mm to line up the chain with the rear sprockets. But in most cases one cup is "fixed", meaning it has a sort of lip or flange on the outside end that determines how far it can be screwed in. Usually this fixed cup (if either is fixed) is on the right (sprocket) side (but of course the threads of the cup might say otherwise).
So normally the fixed cup is screwed in until it's flange is tight against the BB housing, and then the other cup is screwed in sufficiently to achieve proper bearing motion.
But it's unclear whether the flange is present on your cups. It sorta looks like there's something on the left cup in your top picture, but it's hard to say for sure.
Note that, unless a cup has a flange on it so that it's screwed tight against the BB housing, there should be a lock rings installed to maintain the position of the cup and hence the adjustment of the bearings.