Check 7 / 12 LOW impact In the full checklist
Video <800kb, poster image, no auto HD stream
What this check is
A hero video that starts streaming at full resolution competes for the bandwidth the page needs. A compressed clip with a poster frame and no autoplay HD stream keeps the video without paying for it on every visit.
How to implement it
Compress the clip to web-optimised H.264 or VP9 under a megabyte, set the poster image, disable preload of the full file and cap the resolution served to phones. Let the shopper start the video rather than autoplaying the heavy version.
How to verify it
Load the page on throttled mobile and confirm the poster appears immediately, the video file is not requested until play, and the largest contentful paint is a still image rather than the video.
All 197 checks, one Google Sheet
This page is the summary. The full checklist carries the priority, the impact score and the tool link for every check — all 197 of them, across 14 categories, as a Google Sheet and CSV with lifetime updates.
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