I just saw that
cdn.shoplightspeed.com is already using Cloudflare. So it seems LightSpeed CMS is already using Cloudflare, but they probably have not enabled the Cloudflare Feature Polish, or it could not improve your images size under the given settings.
Nearly impossible not to improve a PNG picture by converting tho, so I assume they have not enabled Polish.
What you can do is: ask them nicely if they are willing to spend $20/month on Cloudflare’s Pro Plan for their customers satisfaction.
On Pro Plan ($20/month) Cloudflare will get Polish enabled for them so they will be able to deliver your images as WEBP which then are getting served from their cdn-domain more optimized.
On Business Plan ($200/month) they can even activate Image Resizing which will scale down the image to fit the displayed resolution automatically.
As I myself never used LightSpeed CMS I would recommend you just reaching out to them and ask them to consider upgrading their Cloudflare Plan or if they already are on paid plan to activate these features.
But fact is the domain:
shoplightspeed.com is using Cloudflare: https://dnschecker.org/#NS/shoplightspeed.com
cdn.shoplightspeed.com is getting proxied through Cloudflare: https://dnschecker.org/#A/cdn.shoplightspeed.com