Look at the comment by katheenkat, two comments below mine. You can't just put an archer into any stance you like when an arrow is drawn and pointed at something. Though it may be artistically appealing, it's not something a lot of people like to see when a bow and arrow is used incorrectly. It makes it seem like you're not researching what you're trying to draw; archery isn't something just in fantasy, it's a real weapon with correct and incorrect ways to use it.
^ This is a good reference for archery stances.