rem: this._monitor.style.backgroundColor = "white"; 
add: var tileWidth = Math.floor(this._image.naturalWidth * width / screen.width); var tileHeight = Math.floor(this._image.naturalHeight * height / screen.height); var ctx = canvas.getContext("2d"); for (var x = 0; x < width; x += tileWidth) { for (var y = 0; y < height; y += tileHeight) { ctx.drawImage(this._image, x, y, tileWidth, tileHeight); } } 
context:   _tileImage: function ()  {    var bundle = document.getElementById("backgroundBundle");    this._monitor.style.backgroundColor = "white";    var text = document.createElementNS(kXUL_NS, "label");    text.setAttribute("id", "noPreviewAvailable");    text.setAttribute("value", bundle.getString("DesktopBackgroundNoPreview"));    this._monitor.appendChild(text);  },
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/10234/0f6c796a9092e485b60cb45ef78e7df257df2195/setDesktopBackground.js/buggy/browser/components/shell/content/setDesktopBackground.js