Which is better working on HTML, % or px

Question

When working on an HTML site and placing images or videos, the site is gonna be used for for pc and phones.
But when using % it would be different for each platforms, same goes with px. So which one should we use to be better for both?

Answer 1

You already seem to know the difference in devices but certain images in general may strongly be effected by % verses px so there really is no absolute.
Unfortunately everything SVG like

Answer 2

Thanks