holder.js
function visibilityCheck() {
	    var renderableImages = [];
	    var keys = Object.keys(App.vars.invisibleImages);
	    var el;

	    keys.forEach(function (key) {
	        el = App.vars.invisibleImages[key];
	        if (dimensionCheck(el) && el.nodeName.toLowerCase() == 'img') {
	            renderableImages.push(el);
	            delete App.vars.invisibleImages[key];
	        }
	    });

	    if (renderableImages.length) {
	        Holder.run({
	            images: renderableImages
	        });
	    }

	    // Done to prevent 100% CPU usage via aggressive calling of requestAnimationFrame
	    setTimeout(function () {
	        global.requestAnimationFrame(visibilityCheck);
	    }, 10);
	}
function visibilityCheck() {
	    var renderableImages = [];
	    var keys = Object.keys(App.vars.invisibleImages);
	    var el;

	    keys.forEach(function (key) {
	        el = App.vars.invisibleImages[key];
	        if (dimensionCheck(el) && el.nodeName.toLowerCase() == 'img') {
	            renderableImages.push(el);
	            delete App.vars.invisibleImages[key];
	        }
	    });

	    if (renderableImages.length) {
	        Holder.run({
	            images: renderableImages
	        });
	    }

	    // Done to prevent 100% CPU usage via aggressive calling of requestAnimationFrame
	    setTimeout(function () {
	        global.requestAnimationFrame(visibilityCheck);
	    }, 10);
	}
function visibilityCheck ( ) { var renderableImages = [ ] ; var keys = Object . keys ( App . vars . invisibleImages ) ; var el ; keys . forEach ( function ( key ) { el = App . vars . invisibleImages [ key ] ; if ( dimensionCheck ( el ) && el . nodeName . toLowerCase ( ) == 'img' ) { renderableImages . push ( el ) ; delete App . vars . invisibleImages [ key ] ; } } ) ; if ( renderableImages . length ) { Holder . run ( { images : renderableImages } ) ; } // Done to prevent 100% CPU usage via aggressive calling of requestAnimationFrame setTimeout ( function ( ) { global . requestAnimationFrame ( visibilityCheck ) ; } , 10 ) ; }
Iterates through all current invisible images, and if they're visible, renders them and removes them from further checks. Runs every animation frame.

@private
Iterates through all current invisible images and if they re visible renders them and removes them from further checks . Runs every animation frame .