JSFiddle - React, Tailwind, and code Playground

HTML

<img id="pic" data-bind="attr: { src : imgsrc }" />

JavaScript

var myViewModel = {
    imgsrc: ko.computed(function () {
        var pic = document.getElementById('pic');
        pic.onerror = function () {
            pic.src = 'http://blog.extreme-advice.com/wp-content/uploads/2013/01/error.png';
        };
        return 'http://images.nationalgeographic.com/wpf/media-live/photos/000/604/cache/best-pictures-cassini-mosaic-saturn-rings_60498_600x450.jpg';
    }, this)
};

ko.applyBindings(myViewModel);