Manipulating images through the Javascript Canvas API is great. It allows the developer to apply powerful transformations to an image before displaying it on a web page. Despites its power, the Canvas API also has a limitation that can be extremely annoying: not respecting CORS "taints" the canvas, which severely ampers its most basic uses (see the MDN article about it)

I have the URI to a Flickr photo (say the picture of a friend for example) and I want to apply a given transformation to the image before displaying it on my webpage. Two choices then:

1. Cropping the image myself with some random Adobe tool or Picasa / Aviary / whatever
2. Using the canvas API to do it on the fly in web page