Google Pagespeed ignores converted images on Mobile

Thread Starter


In my .htaccess I have this

### marker WEBP start ###

RewriteCond %{HTTP_ACCEPT} "image/webp" RewriteRule .* - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+webp] RewriteCond %{HTTP_USER_AGENT} iPhone.*Version/(\d{2}).*Safari RewriteCond %1 >13 RewriteRule .* - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+webp]

### marker WEBP end ###

However these rules should not enough to cover all mobile situations , am I right ?

Hi @gomoot,

Thank you for your message. Do not worry, I will try to explain you everything below.

Maybe at the beginning a point of clarification – the rules from the .htaccess file you sent do not apply to my plugin. My plugin adds its rules in the /wp-content directory. Please remember that using several image optimization plugins may cause problems. Decide on one tool.

I ran a test on your website. I simulated browsers with and without WebP support to make sure everything was working. Thanks to this, I can check how much your original images weigh (i.e. what was before installing our plugin) and how much the images converted by our plugin weigh.

Here are the results of my tests:

This means that the plugin is working properly and all images are displayed in the version converted by the plugin.

Please, take a look on your website loading time in my screenshots (you will find it on the bottom bar as “Load” value – marked in red). I tested it on my computer, limiting the internet speed to 10 Mbps. Remember please that mobile internet is often several times lower. I consider it to be a real benefit for your website visitors.

Below I have attached the tutorial describing how to test the plugin:

I also did a test in PageSpeed and I don’t see anywhere that PageSpeed doesn’t see images in WebP format. In my opinion, everything works fine in this matter.

I also recommend you to try the AVIF format on your website. I did an analysis to learn more about the potential benefits of using the AVIF format for you. Images converted to the AVIF format on your website will weigh 58% less than images converted to WebP only, maintaining even better image quality. This will further improve the performance of your website.

Please remember that image optimization is a very important step in optimizing your entire website, but it is not a solution to all problems. In my opinion, the effect of optimizing images on your website is fantastic. You should look for the source of your website performance problem in other things.


Thread Starter


Thank you,I’ll check better.


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