A poster image rescued a 5.2s LCP from a hero video

A poster image rescued a 5.2s LCP from a hero video

When your hero is an autoplay video, LCP — Largest Contentful Paint — often waits for the video to start, which can be painfully slow on mobile. Think of it like waiting for a band to set up before the show, when a printed photo of the stage would do for the opening seconds.

A landing page had a 6 MB background video with no fallback. On phones, LCP hit 5.2s.

The fix gave the browser something instant to show:

— Added a lightweight poster image (a single 80 KB frame) to the video tag.
— The poster counts as LCP and appears immediately.
— The video then loads quietly behind it.

Result: LCP dropped to 2.3s. Visitors saw a sharp first frame at once.

Try this: if you use a hero video, always set a poster. It's a one-line safety net.