Sorry, the wiki is currently out-of-date. To load an image blob into a canvas, call canvas.decode(blob). In other words, load and toBlob have been renamed decode and encode.
canvas.getContext('gears-2d') is disabled for the official builds, as
it is still incomplete. If you build from source, you can play with
the work-in-progress 2D context.
To display an image from a blob, one option is to bind a URL to that
blob, via resourceStore.captureBlob, and then point an <img>'s src to
that URL.
