(function($){ $.randomImage = { defaults: { //you can change these defaults to your own preferences. path: 'images/summer2016/', //change this to the path of your images myImages: ['hanabi.gif', 'hirune.gif', 'kingyou.gif', 'koorimizu.gif', 'natsuyasumi.gif', 'ryoufuu.gif', 'senkou.gif', 'tsuyu.gif', 'yuudachi.gif'] //put image names in this bracket. ex: 'harold.jpg', 'maude.jpg', 'etc' } } $.fn.extend({ randomImage:function(config) { var config = $.extend({}, $.randomImage.defaults, config); return this.each(function() { var imageNames = config.myImages; //get size of array, randomize a number from this // use this number as the array index var imageNamesSize = imageNames.length; var lotteryNumber = Math.floor(Math.random()*imageNamesSize); var winnerImage = imageNames[lotteryNumber]; var fullPath = config.path + winnerImage; //put this image into DOM at class of randomImage // alt tag will be image filename. $(this).attr( { src: fullPath, alt: winnerImage }); }); } }); })(jQuery);