Write some Software

I have a wordpress website using the popular plugin Fancy Product Designer which allows users to customize a image in a HTML5 canvas box and then save it so that other users can view it inside the product designer or edit it. Theres an option to allow people to download an image of the canvas window to their PC. Basically what I need done is to have a "submit" button on the bottom of the Fancy Product Designer window which will take the image of the canvas screen and add it to a new wordpress post that way users can share a URL with an image to their creation.