Editorial Mad Slider thumbnails

Hello, I’m using the editorial mag slider with thumbnails on my home page and the thumbnails seem to slow the site way down. On GT metriz it gets an F for Serve Scale Images and says this for each thumbnail

https://bestcappers.com/wp-content/uploads/2019/04/Choosing-The-Right-Sports-Handicapper-For-You-580×375.jpg is resized in HTML or CSS from 580×375 to 151×98. Serving a scaled image could save 77.8KiB (93% reduction).

Does anyone know a way to fix this? A plugin maybe? Thank You for any help