Image.getUrl ()
return the url of the image

Sourcecode in Image/objectFunctions.js:
1:   function getUrl() {
2:      res.push();
3:      this.site.staticUrl("images/");
4:      res.write(this.filename);
5:      res.write(".");
6:      res.write(this.fileext);
7:      return res.pop();
8:   }