Twenty thirteen header image

There is a file called header.php in the theme folder
hope that helps

In header.php there is html code no css.
I want css where I can change the size of image and do other stuff on image.

It’s not in style.css, but output inline within the code:

<style type="text/css" id="twentythirteen-header-css">
.site-header {
   background: url(https://sandbox.geefamily.net/wp-content/themes/twentythirteen/images/headers/circle.png) no-repeat scroll top;
   background-size: 1600px auto;
}
</style>

Because the image is the background property of the header element, you can’t really resize it the same way that you can HTML img elements. That is, if you try to set the size, you will end up cropping the image rather than resizing it proportionally.

There have been quite a few threads about trying to make the header image responsive (i.e., resize proportionally). If that is what you are trying to do, you can check out this thread. Otherwise, you should be able to add your own CSS through either a child theme or a CSS plugin and override the CSS rule above.

Thanks Bruin,

But I am unable to find this code in header.php ,that you written above.
Please tell me that where can i find this code.
In style.css there is the css for
.site-header{ background: none !important.}
but i can not understand.
Please help.

If you look closely, that rule is inside a media query for print; that prevents the header image from being printed (I guess they assume that most people wouldn’t want to see the header image on printed output).

The code I mentioned earlier is output by custom-header.php. If you plan on making changes to that file, please create a child theme first and make your changes on a copy of that file. Otherwise, if the theme ever gets upgraded because of feature enhancements or security patches, your changes will get overridden and lost.

I’m not sure why you want to make changes to the file, though; is there something you want to do that can’t be done with just CSS?

Actually i am learning how to work with wordpress.
For this i am trying to make this sample web page…

Here the header image is in center..means there is some space left in right and left side.
But in twenty thirteen header image takes full space.
So i am thinking to change the css of header…but i can not find that.
Hope now you got what i really want to do.
Thanks