How about using SVG instead? SVG is supported in all major browsers since IE 9. As a text-based format, it's small, lightweight, and easy to manipulate.
A quick-and-dirty approach is to use SVG-edit (online) or Inkscape (download) to create your drawing, then simply drop the resulting <svg>
element onto your HTML page. Here's a fiddle showing how that could work: http://jsfiddle.net/t6fAb/
Better yet, use SVG.js to create the drawing entirely in JavaScript. Here's a fiddle showing how that could work: http://jsfiddle.net/WEL4J/