Manuel Cervera

I have found this in “functions” file:

define( 'HEADER_IMAGE_WIDTH', apply_filters( 'yoko_header_image_width', 1102 ) );
define( 'HEADER_IMAGE_HEIGHT', apply_filters( 'yoko_header_image_height', 350 ) );

I fugure out that changing HEIGHT I could the heingt of the images, couldn’t I? I am interested in this.

I have also found this:
define( 'NO_HEADER_TEXT', true );

I figure out that changing true to false I could put text in the header.

And I found this too:

register_default_headers( array(
         'ginko' => array(
         'url' => '%s/images/headers/ginko.jpg',
         'thumbnail_url' => '%s/images/headers/ginko-thumbnail.jpg',
         /* translators: header image description */
         'description' => __( 'Ginko', 'yoko' )
         ),
         'flowers' => array(
         'url' => '%s/images/headers/flowers.jpg',
         'thumbnail_url' => '%s/images/headers/flowers-thumbnail.jpg',
         /* translators: header image description */
         'description' => __( 'Flowers', 'yoko' )
         ),
         'plant' => array(
         'url' => '%s/images/headers/plant.jpg',
         'thumbnail_url' => '%s/images/headers/plant-thumbnail.jpg',
         /* translators: header image description */
         'description' => __( 'Plant', 'yoko' )
         ),
         'sailing' => array(
         'url' => '%s/images/headers/sailing.jpg',
         'thumbnail_url' => '%s/images/headers/sailing-thumbnail.jpg',
         /* translators: header image description */
         'description' => __( 'Sailing', 'yoko' )
         ),
         'cape' => array(
         'url' => '%s/images/headers/cape.jpg',
         'thumbnail_url' => '%s/images/headers/cape-thumbnail.jpg',
         /* translators: header image description */
         'description' => __( 'Cape', 'yoko' )
         ),
         'seagull' => array(
         'url' => '%s/images/headers/seagull.jpg',
         'thumbnail_url' => '%s/images/headers/seagull-thumbnail.jpg',
         /* translators: header image description */
         'description' => __( 'Seagull', 'yoko' )
         )
   ) );
}
endif;

Changing names I can put the images I want, right?
How could link pictures here?
What does “header image description” mean?
What does “description ‘=> __ (‘ Seagull ‘,’ yoko ‘)” mean?
How could assign a picture to each page

Sorry my questions, but I am not a programmer and I need to solve this for my website.
Thanks a lot.