NellieBird

Great!

It doesn’t mean you have a smaller sized brain, just less knowledge. I placed a container (div) around my header image in header.php, and gave it the id=header_container. You can see it in the code below (the first and last line):

<div id="header_container">

	<?php
				// Check to see if the header image has been removed
				$header_image = get_header_image();
				if ( $header_image ) :
					// Compatibility with versions of WordPress prior to 3.4.
					if ( function_exists( 'get_custom_header' ) ) {
						// We need to figure out what the minimum width should be for our featured image.
						// This result would be the suggested width if the theme were to implement flexible widths.
						$header_image_width = get_theme_support( 'custom-header', 'width' );
					} else {
						$header_image_width = HEADER_IMAGE_WIDTH;
					}
					?>
			<a href="<?php echo esc_url( home_url( '/' ) ); ?>">
				<?php
					// The header image
					// Check if this is a post or page, if it has a thumbnail, and if it's a big one
					if ( is_singular() && has_post_thumbnail( $post->ID ) &&
							( /* $src, $width, $height */ $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), array( $header_image_width, $header_image_width ) ) ) &&
							$image[1] >= $header_image_width ) :
						// Houston, we have a new header image!
						echo get_the_post_thumbnail( $post->ID, 'post-thumbnail' );
					else :
						// Compatibility with versions of WordPress prior to 3.4.
						if ( function_exists( 'get_custom_header' ) ) {
							$header_image_width  = get_custom_header()->width;
							$header_image_height = get_custom_header()->height;
						} else {
							$header_image_width  = HEADER_IMAGE_WIDTH;
							$header_image_height = HEADER_IMAGE_HEIGHT;
						}
						?>
					<img src="<?php header_image(); ?>" width="<?php echo $header_image_width; ?>" height="<?php echo $header_image_height; ?>" alt="" />
				<?php endif; // end check for featured image or standard header ?>
			</a>
			<?php endif; // end check for removed header image ?>

			<?php
				// Has the text been hidden?
				if ( 'blank' == get_header_textcolor() ) :
			?>

				</div>  <!-- #header_container -->

Then I gave the header_container its dimensions and position in my (child)theme’s style.css:

#header_container {
	position: absolute;
	top: 10px;
	left: 380px;
	width: 370px;
	height: 175px;
	z-index: 9999;
}

Hope that helps!

Thx aikorei for your reply. In the mean time I’ve worked out something that does what I want: I pasted the code below in my functions.php, and in addition to that I placed a div around the header img in my header.php. I gave the div the exact dimensions of what I want the pic to be. That did it.

remove_filter( 'HEADER_IMAGE_WIDTH', 'twentyeleven_header_image_width' );
remove_filter( 'HEADER_IMAGE_HEIGHT', 'twentyeleven_header_image_height' );
define( 'HEADER_IMAGE_WIDTH', apply_filters( 'child_header_image_width', 370 ) );
define( 'HEADER_IMAGE_HEIGHT', apply_filters( 'child_header_image_height', 175 ) );

@aikorei: could you please put down the code that you used in your child’s functions php and/or any other code you used to make it work? I did put the underneath code in my child’s functions.php, yet still have the problem as you mentioned at first. In the Appearance > Header it even shows the preview in the right dimensions, but on the actual page it shows stretched to 1000px.

$defaults = array(
	'default-image'          => '',
	'random-default'         => false,
	'width'                  => 370,
	'height'                 => 175,
	'flex-height'            => false,
	'flex-width'             => false,
	'default-text-color'     => '',
	'header-text'            => true,
	'uploads'                => true,
	'wp-head-callback'       => '',
	'admin-head-callback'    => '',
	'admin-preview-callback' => '',
);
add_theme_support( 'custom-header', $defaults );

that worked, by adding remove_filter('dbem_notes', 'wpautop'); Not sure what effect that will have on my other pages, but as for now this is fixed. Thanks!