Page Speed is taken very seriously by a lot of Magento stores since it directly influences your general website performance. That's why everyone constantly tries to improve it and looks for the best ways to do so.
In case you're checking your website speed in Google PageSpeed you can face the Serve images in next-gen formats issue. According to it, Google recommends you to save images in JPEG 2000, JREG XR and WEBP formats instead of old PNG and JPG. Best of all - WebP.
Never heard of it?
Find out more about what is WebP, why should you use it in your Magento 2 store and how is it different from PNG and JPG in this article about WebP images in Magento 2.
Implementing this Google recommendation gives you an advantage and allows to reduce the size of images by half.
Fortunately, there is no problem that wouldn't have a solution. So, to solve the Serve images in next-gen formats issue you have to install and enable the Magento 2 WebP Images Extension.
This module allows you to convert all current and future images into WebP file format manually and automatically with no complex configurations.
All you have to do is to set the quality you want the converted images to and continue to upload the original PNG and JPG images. Magento 2 WebP Images extension will do the rest.
You might be thinking that nothing is that easy. What about the browsers that don't support WebP format yet?
WebP Images module creates a copy of your original images, so if someone enters your website from any of those browsers that don't support WebP they won't see broken images, but original PNG and JPG.
Website performance hugely depends on images since they take the biggest part of data on your Magento website. So following Google's advice and optimizing images is one of the first steps to improved website loading speed and SEO.
However, there may be some other factors that influence your website speed. Check out the article about Top 10 Best Free Speed Testing Tools to analyze your Magento 2 website performance and learn what to improve.