quick image resizer for node

resizer.js

var fs = require('fs');
var im = require('imagemagick');

// define source of pictures:
var source_dir = '/source'

// define output of resized pictures:
var output_dir = '/output'

//define image sizes
var widths = ['270', '590', '910', '1230'];


var source_dir = process.cwd()+'/source/';
var output_dir = process.cwd()+'/output/';

fs.readdir(source_dir, function(err, files){
	if (err) throw err;
	resize_all(files);
});

function resize_all(files){
	for (n = 0; n < files.length; n++){
		var source_arr = files[n].split('.');
		for (i = 0; i < widths.length; i++){
			im.resize({
				srcPath: source_dir + files[n],
				width:   widths[i],
				dstPath: output_dir + source_arr[0] + '_w' + widths[i] + '.' + source_arr[1],
				quality: 1,
				progressive: true
			},
			function(err, stdout, stderr){
			  if (err) throw err
			});
			  console.log('done with ' + source_arr[0] + '_w' + widths[i] + '.' + source_arr[1]);
		}
	}
}