Polyvore users create over 3 million sets every month, mixing and matching their favorite products to express their style. They clip in images from all over the web, like this teal T-shirt from nordstrom.com
As you can see, the shirt image has a light gray background that creates an eyesore when layered with other items in a set:
How do we strip this background away in order to achieve a cleaner look? More importantly, how can we do it for not just this T-shirt, but for any of the 2.2 million images our users clip in every month?