This is pretty cool. You might even be able to turn this into a business if you could actually order the sweaters. Extra bonus points if you could do that without it being screen printed on.
It doesn't handle rotated images correctly. Many of the images I tried with my iPhone came out turned sideways or upside down. (I believe this is because the iPhone stores the correct orientation in the exif data.)
I worked on a similar project once (fully-client-side image cropping), and you are correct about the EXIF data. There was a library out there that saved my ass with that problem, but it escapes me now.
It doesn't handle rotated images correctly. Many of the images I tried with my iPhone came out turned sideways or upside down. (I believe this is because the iPhone stores the correct orientation in the exif data.)