Maisie Williams is holding Needle left handed like Arya; however Maisie is right handed.

She insisted on learning lefty style.

Redditor A_Polite_Noise explains:

This is an old picture (April 2010); I remember when GRRM posted it on his livejournal. 

This is a very young Maisie Williams (12) having received the ValyrianSteel.com replica of the sword (not the show Needle HBO made) and practicing with it near her house just after being cast; her mother took this and other pictures. 

This was before she had filmed any scenes yet. A lot of fans were pleased because in other pictures from the set, you see that she (despite being right handed) was practicing with her left hand because her parents told her Arya was left handed in the books.

Here is the original post: http://grrm.livejournal.com/146489.html

And what do we say to the God of Death? Not today.

More Needle:

http://pandawhale.com/post/43594/arya-with-her-bff-needle

http://pandawhale.com/post/29831/arya-stark-and-needle