Retina header for WordPress

Hi and good day,

For the header image, I want to use a 2x size image (W: 2340px).

WP doesn’t allow the user to do this.

I need to know the class/ id which defines the header image.

What I tried is

div#header img

but this doesn’t seem to work.

[How to Fix the Blurry Logo on Your WordPress Site | Compete Themes](https://www.competethemes.com/blog/blurry-logo-wordpress/) has some CSS but it only applies to their specific theme.

.custom-logo,
.site-header .logo {
  max-width: 100% !important;
  width: 450px !important;
  height: auto !important;
}

/
Any advice would be greatly appreciated!

With best regards,
Omar KN