function get$0() {
      //return a PImage of curContext
      var c = new PImage(p.width, p.height, PConstants.RGB);
      c.fromImageData(curContext.getImageData(0, 0, p.width, p.height));
      return c;
    }
This function load images on a separate thread so that your sketch does not freeze while images load during
setup(). While the image is loading, its width and height will be 0. If an error occurs while loading the image,
its width and height will be set to -1. You'll know when the image has loaded properly because its width and
height will be greater than 0. Asynchronous image loading (particularly when downloading from a server) can
dramatically improve performance.
The extension parameter is used to determine the image type in cases where the image filename does not end
with a proper extension. Specify the extension as the second parameter to requestImage().

@param {String} filename        name of file to load, can be .gif, .jpg, .tga, or a handful of other image
                                types depending on your platform.
@param {String} extension       the type of image to load, for example "png", "gif", "jpg"

@returns {PImage}

@see PImage
@see loadImage