Properly size images, Serve images in next-gen formats

Thanks for reaching out. These recommendations you’re encountering are not specific to the AMP plugin. If opening the full recommendation details you’ll find some useful information for each highlighted area.

The “Duplicate modules in JavaScript bundles” recommendation may change once there are updates to the below GitHub issue, on the AMP projects GitHub repository:
https://github.com/ampproject/amphtml/issues/28638

I need the quote which format of images is better in AMP sites to load faster. Please let me know.

The click through link next to the recommendation within PageSpeed Insights provides more information that I can here, with the same details applying to AMP URLs as it does non AMP URLs.

You can experiment yourself with any images if you use a service such as squoosh.app. You’ll find you can make similar image file size reductions using jpeg images, not just webp images – which isn’t fully supported yet in WordPress without a plugin:
https://core.trac.www.ads-software.com/ticket/35725

Also, for images I suggest using Jetpack plugin’s Site Accelerator image CDN (aka Photon) as one way to serve properly-sized images in modern formats without having to do anything manually.

We’re going to be investigating ways of providing better guidance for image performance in the plugin.

I’ve filed an issue regarding this: https://github.com/ampproject/amp-wp/issues/5788