For every additional millisecond your page takes to load, more of your users abandon your site and their shopping carts. Images, although proven to increase users’ affinity towards your product, can slow down your site when not properly optimized.
To make sure that your images only have a positive effect on your users, you can both transform images on-the-fly (as opposed to storing multiple variations of one source image) and use a CDN network to deliver your files. Filestack enables you to do both with ease.