One of the easiest ways to improve your site loading time is to serve smaller images using an image format that handles image compression better. One of the newer image formats for dealing with site optimization is WebP. The WebP image format typically will produce an image that is 30% smaller than the JPG version.
There are a number of plugins that will handle WebP image conversion for your site.
EWWW Image Optimizer
EWWW Image Optimizer is a plugin that has a large number of features and optimizes all site images to WebP using the bulk optimizer. If you are using the Cache Enabler plugin for a full-page cache you can use the serve WebP feature that it includes.
The Imagify plugin includes a service that deals with WebP image conversion. Imagify includes the option to keep your original images before being optimized as well as keeping a separate image optimized version of the WebP image version.
The ShortPixel plugin includes a service that will optimize site images and WebP image conversion. ShortPixel also has on-the-fly image conversion using their CDN. ShortPixel also includes integration in the Autoptimize plugin for the ShortPixel CDN supporting on-the-fly image conversion for WebP and AVIF image formats.
The last plugin that is going to be covered is Webp Express. The WebP Express plugin will allow you to bulk convert site images to the WebP image format and then serve those out on the site without much setup.
If you care about having a fast site for your site users then being able to serve out a WebP image version will improve your site load time.