gistfile1.js

app.get('/img/:x/:y/:name', function(req,res){
	var x 	= req.params.x,
		y 	= req.params.y;
	var sub = req.params.name.split('.'),
		name = sub[sub.length-2],
		ext = sub[sub.length-1];
	var d1 = ['/path/to/',name,'.',ext];
	fs.exists(d1.join(""), function(exist){
		if(exist){
			var image = Canvas.Image,
				img = new image;
			img.onerror =  function(err){
				throw err;
			};
			img.onload = function(){
				var canvas = new Canvas(x,y);
				var ctx = canvas.getContext('2d');
				ctx.imageSmoothingEnabled = true;
				ctx.drawImage(img,0,0,x,y);
				canvas.toBuffer(function(err,buf){
					res.writeHead(200, {'Content-Type': 'image/'+ext });
					res.end(buf,'binary');
				});
			};
			img.src = d1.join("");

		}else{
			res.status(404);
		}
	});
});