Spur is an app that is an easy way to critique your web designs in ways you’ve never done before. Just paste a URL (or upload an image) and you’ll be able to use seven different tools (Grayscale, Intersections, Contrast, Blur, Mirror, Rotate, 50% Zoom) to help you find what’s working and see things you might have missed.
Spur generates a unique URL you can use to share your design with any of the tools applied to it.