Add Warning in Docs about Lazy Loading and LCP

[colbyfayock]

Next.js adds a warning in dev mode for images that might impact LCP. While we might not have a way to provide a similar warning, where on the docs can we add a note along with best practices for delivering images as high priority in the right situations?

Perhaps its a guide? Should a note be on the CldImage basics page? With a link to the guide?

[colbyfayock]

Nex.tjs example: https://github.com/vercel/next.js/blob/47b9fc6128a2f65d71b1e55f107708cb39308860/packages/next/src/shared/lib/get-img-props.ts#L570-L605

LCP Measurement: https://web.dev/articles/lcp#measure-lcp-in-javascript