gistfile1.js

app.get('/img/:width/:height/:name', function(req,res){
	var name = req.params.name;
	var sub = name.split('.'),fname = sub[sub.length-2],ext = sub[sub.length-1];
	var d1 = ['/path/to/',fname,'.',ext];

	fs.exists(d1.join(""), function(exist){
		if(exist){
			var img = new image;
			console.log(d1.join(''));
			img.onerror =  function(err){
				throw err;
			};
			img.onload = function(){
				console.log('processing image');
				var canvas = new Canvas(req.params.width,req.params.height);
				var ctx = canvas.getContext('2d');
				ctx.imageSmoothingEnabled = true;
				ctx.drawImage(img,0,0,req.params.width,req.params.height);
				canvas.toBuffer(function(err,buf){
					switch(ext){
						case 'jpg':
							res.setHeader('Content-type','image/jpeg');
							break;
						case 'png':
							res.setHeader('Content-type','image/png');
							break;
						case 'gif':
							res.setHeader('Content-type','image/gif');
							break;
						default:
							break;
					}
					if(err){
						console.log('Error serving image '+d1.join(""));
						console.log('Error: '+err);
						res.status(500);
						res.end();
					}else{
						res.status(200);
						res.end(buf,'binary');
					}
				});
			};
			img.src = d1.join("");

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