People access your website from multiple types of devices like phones, tablets, laptops, desktop computers, Smart TVs and probably someone browsers the internet using a Smart Refrigerator...
It comes a time on the design process were using the same image for desktop and mobile devices doesn't work. Using a wide hero image on the desktop may look nice, but when you go to a mobile device, the details on the image get lost, and the products are barely visible...
If you're a designer or a developer, it's clear to you that you need to manage the assets and optimize images for different devices and screen sizes. There are also two types of images that you need to work with...