Remove erroneous check for resource initiator type when considering whether to submit LCP background image #1760
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…ether to submit external background image
westonruter
added
[Type] Bug
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Summary
When setting up a demo site with Optimization Detective, I was confused when I wasn't getting the
lcpElementExternalBackgroundImagedata submitted with the URL Metric. In looking at the console, I saw:This was strange because the LCP element was definitely using a
background-imagecoming from a stylesheet:Nevertheless, the
initiatorTypeof the resource was coming through as animgand not ascss. Then I looked further down the page and I found the same image was being used in anIMGtag:This actually reveals an interesting performance fact: even though the image is being used as a background image for the LCP element, there is an image way further down the page which is actually initiating the loading of this image before the stylesheet is initiating the load. Even more surprising, this
IMGhasloading=lazy. This highlights the need for adding a preload link for this image URL so that it is properly prioritized!Granted, it may be unlikely for the exact same image used as the LCP element's background to also appear further down the page in non-example content. In any case, checking the
initiatorTypefor the resource was redundant because it's already aborting if the LCP element is anIMGtag:performance/plugins/image-prioritizer/detect.js
Lines 90 to 98 in 2033d44
Therefore, there is no need for the additional check.