I have found in the past that it is very hard to draw small sprites effectively by starting out with line art.  Obviously there are some parts of the body that even a single pixel width can distort.  In your sprite, the legs are the victim.  I would retry this sprite by using a silhouette method.  Don't waste your pixel space by drawing an outline, use the canvas space to make the legs look more natural and not all lumpy in the thighs.