"Image elements do not have explicit width and height" means that your webpage is not setting explicit width and height attributes on image elements, which can cause layout shifts as images load.
This Guide helps you solve common problems with PageSpeed and Lighthouse that can affect your website's SEO and make it harder for people to use. Each article gives easy, step-by-step instructions on how to fix these issues and improve your site.
"Reduce the impact of third-party code" means that third-party code on your webpage is slowing down your site.
"Ensure text remains visible during webfont load" happens when your webpage is displaying invisible text while webfonts are loading, leading to a poor user experience.
"Avoid an excessive DOM size" means that your webpage has a large Document Object Model (DOM) tree, which can slow down your site.
"Properly size images" means that your webpage is serving images that are larger than necessary for their display size, leading to wasted data and slower load times.
"Reduce unused CSS" means that your webpage is loading CSS rules that aren't being used, which can slow down your site.
"Defer offscreen images" means your webpage is loading images that aren't immediately visible to the user. This unnecessary loading can slow down your site.