Ask HN: Is this design copyright infringement?

I'm not a designer by any means but I try my best to make my apps look good. While looking for inspiration I found some good images on stock images sites.

Since I'm really new to all this design thing, I started by transforming a comp, anchor point by anchor point, into a vector image. Then I started changing it to my needs.

Is this copyright infringement?

Links: - Original file: http://www.shutterstock.com/pic-55808422/stock-vector-illustration-of-a-cartoon-cute-character-for-use-in-presentations-etc.html - My comp to vector transformation: http://i37.tinypic.com/2rdxo34.png - My final design: http://i36.tinypic.com/11tlmhh.png