[FIG(quote)[
[FIGCAPTION[
[1] [CITE[Page Speed Optimization Libraries: net_instaweb::CriticalImagesBeaconFilter Class Reference]]
([TIME[2016-04-01 17:16:52 +09:00]] 版)
<http://modpagespeed.com/psol/classnet__instaweb_1_1CriticalImagesBeaconFilter.html>
]FIGCAPTION]

> Inject javascript for detecting above the fold images after the page has loaded. Also adds pagespeed_url_hash attributes that the beacon sends back to the server. This allows the beacon to work despite image URL rewriting or inlining.

]FIG]


[FIG(quote)[
[FIGCAPTION[
[2] ([TIME[2016-04-01 17:17:10 +09:00]] 版)
<http://wha2up.com/category/staffdiary>
]FIGCAPTION]

> <img src="http://wha2up.com/wp-content/uploads/2015/05/210x70xrogo.jpg.pagespeed.ic.0mUFWYk5aL.webp" width=210 height=70 valign="center" pagespeed_url_hash="3404950283" onload="pagespeed.CriticalImages.checkImageForCriticality(this);">

]FIG]