WordPress output all my images with bad value (px) instead of digit only

Hi Everybody,

I’m testing my website for SEO purpose, however wi’m having a a really bad score in the coding mark from https://nibbler.silktide.com/

The main reason, due that wordpress output all my images in pixels in the html instead of digit only

“Bad value 390px for attribute width on element img: Expected a digit but saw p instead.”

If i see n the html output, yes it display px instead of digit only in the width on height of the <img>.

Anybody know a solution for this by any chance ? It will be fantastic,

Thank you !