image-optimization

Having an ecommerce website, We have thousands of product images. On checking pagespeed on google it shows me something like this: I was wondering, if there is any built in feature in Java or any third party library is available with which we can losslessly compress all the images that we host. Hence we can save few KBs of our customers. On searching through internet I found few like punnypng and kraken which are paid, hence we do not have heavy image uploaded every month, subscribing to them is not worth. I would prefer any built in feature in Java or any open source third party library. I

The bundling of JS and CSS files won't be necessary in HTTP/2 , but what about image sprites? Looking at the demo it seems that it already works way faster than HTTP/1.1, but won't bundling images into sprites make it even faster? I mean, won't the PNG's optimization algorithms work better when all the data is in a single file? It depends of your image(s) sizes and format. If the images are big enough, you won't gain much by using sprites, but for small images there are significant gains, even when using HTTP/2. What makes HTTP/2 better is that there is much less overhead for headers and