Simple pages (simple layout, no complex UI components, few images) load faster.
It’s a no brainer that if you compress your images, you will increase page speed (especially if you pre-render them with Google AMP.)
If you keep adding pixels, the cross-domains calls will degrade performance.
What it might not seem obvious is that mobile pages rank lower than desktop’s in performance, every time, as you can see in Backlinko’s page speed report.
For example, my blog has a nice 91 score for desktop, and an embarrassing 36 for mobile (based on Google PageSpeed report.)
Simple changes like using JPG instead of PNG files, sandboxing third-party pixels, and reducing bots traffic, will help both desktop and mobile performance.