[littl3chocobo]

you can copyright a cartoon though and when someone steals a frame of that cartoon then what they make of it, in this case a pose, is stolen

saying 'i want to draw a girl with a leg straight and a leg up with an arm tucked in and another out' is not stealing even if the outcome is the sailormoon pose(that is pose-jacking it is something else)

but taking a clip picture or screencap from a copyrighted source and copying/tracing that image is considered copyright infringement, that small piece is protected under copyright law and using it is a violation of the law and while using that stolen base to make something is covered(there is a clause saying if you change something by a certain percent it is no longer a copyright violation and has to be bickered over in court) it still reeks of the unpleasant because it is still from something stolen and it encourages more theft

when you've done that you have gone from taking a pose(which under certain circumstances /can/ be copyrighted) to taking part of a produced piece