What are the best image sizes for the Google Chrome mobile website audit?

I'm making a WordPress website and want to get the best score possible. There will be an image with 100% width on the top page. I just need to find out what sizes Google wants it to be now.

add_image_size( 'iphone-320', '320', '9999', false );

I'm going to add some code like this to the functions.php file of the template.

1 Answer 1


PageSpeed Insights for example isn’t using “real devices” with resolutions.

Also see this post: What is the screen size used by Google's PageSpeed Insights for mobile previews?

I would suggest using image sizes near your css breakpoints (assuming you have a responsive design).

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