random image from imagur every 60 seconds

random-image-background.js

(function () {
    "use strict";

    var parts = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789',
        canvas = document.createElement('canvas'),
        context = canvas.getContext('2d');

    imgur();

    function makeImage(url, cb) {
        var img = new Image();
        img.crossOrigin = 'Anonymous';
        img.onload = cb;
        img.src = url;
    }
    function makeId() {
        var id = '';
        for (var i = 0; i < 5; i++) {
            id += parts.charAt(Math.floor(Math.random() * parts.length));
        }
        return id;
    }
    function checkImage(img) {
        return img.width !== 161 && img.height !== 81;
    }
    function encodeImage(img) {
        canvas.height = img.height;
        canvas.width = img.width;
        context.drawImage(img, 0, 0);
        return canvas.toDataURL('image/png');
    }
    function drawImage(dataUrl) {
        document.body.style.background = 'url(' + dataUrl + ')';
    }
    function imgur() {
        var url = 'http://i.imgur.com/' + makeId() + '.png',
            timeout = 10;
        makeImage(url, function () {
            if (checkImage(this)) {
                drawImage(encodeImage(this));
                timeout *= 6000;
            }
            setTimeout(imgur, timeout);
        });
    }
}());