Starting around Chrome 116, we're making two changes to the way that LCP handles animated images and videos. In both cases, Chrome will count the time that the first full frame is presented as the timestamp for the candidate.
Videos have previously been ignored for LCP, unless they have a poster image. With this change, a video element can become an LCP candidate, exactly like an image. If it is used as a candidate, then the associated timestamp will be the time that the first video frame is presented on screen.
Animated images (animated GIFs and PNGs) were previously not considered as LCP candidates until they were fully loaded. For large files, this could be long after the video has been playing on screen. This change counts the time that the first frame of the animation is displayed, if the image becomes an LCP candidate.
Pages with large auto-playing videos should start seeing that video used as the LCP element. LCP scores may improve or regress on those pages, depending on what element is currently being chosen as LCP.
Pages with large animated images will likely see LCP scores improve, as the image will be reported with an earlier timestamp than before.
This change was launched to Chrome users starting on roughly 2023-08-22, to be rolled out to existing Chrome 116+ installs over a 14 day period.
