Ever thought to add to <img src=””> to your site? Probably not.. Since it doesn’t achieve much. However if you’re building a mobile web-app, all of the images take up precious memory on the mobile device.
A possible optimisation technique is to change the image tags so that only the images in current view are actually displayed and when the user scrolls away they can be removed. Not a bad idea, just don’t set the image src tags to “” because certain browsers don’t know how to interpret this properly and instead of displaying no image they will treat the “” as a relative url meaning the browser will make another request to your site to populate the image.
More details here