flegge

Think I found a way to do it.

Create a child theme (see )

Changed the header.php and replaced the line 44 to:
echo wp_get_attachment_image( $img_id, 'large' );

like theme as well. resizeable logo would be nice or at least something like small/medium/large.

Or could you let us know what we need to change?

Found already:
style.css

.one-column .site-logo img {
	max-height: 340px;
	margin: auto;
}

.site-logo img {
	display: block;
	width: auto;
	max-height: 340px;