Bladders are a "2D" item, meaning they are produced using 2 flat sheets of material that is RF welded together.
Shells are typically a "3D" item, meaning like a tailored piece of clothing they are constructed using multiple pieces of material, usually a front and back panel, and a "edge band" around the outside.
That mean the inflated shape of the bladder (if inflated outside of the wing) and the shell will be somewhat different.
In addition it is desirable for the bladder to be a *bit* larger than the outer shell, just like an inner tube in a bike tire is larger than the volume of the tire casing. That reduces the loads on the welded seams as the shell is the structural element and the bladder is the air tight element.
Having said that the inner bladder need be only a bit larger than the shell. Having the bladder substantially larger increases the weight of the assembly, and more importantly increases the chances of gas getting trapped in folds of the bladder.
Bladders typically require cutting dies and expensive RF welding dies. That means sometimes the same inner bladder is used in several similar wings of different capacity. It works, but is a compromise.
The relative size in these pictures appears to be pretty extreme, but I'd suggest checking with the manufacturer to be sure.
Good luck,
Tobin
