Watermark Images Node.js

water.js

var exec = require('child_process').exec;

function watermark(base,marker,output,callback){
    var command = [
	    'composite',
	    '-watermark', '1x1',
	    '-gravity', 'center', 
	    '-quality', 100,
	    marker,
	    base,
	    output
	];

	exec(command.join(' '), function(err, stdout, stderr) {	
	  return callback(err);
	});
}

if(process.argv.length < 5){
	console.log("Usage: <base> <marker> <output>");
	return;
}

watermark(process.argv[2],process.argv[3],process.argv[4],function(err){
	if(err)console.log(err);
});