Add Image Dimensions Column to Media

<?php
if ( ! function_exists( 'scseed_add_dimensions_column' ) ) {
    function scseed_add_dimensions_column( $columns ) {
        $columns['scseed_dimensions'] = __( 'Dimensions', 'scseed' );
        return $columns;
    }
}
if ( ! function_exists( 'scseed_show_dimensions_column' ) ) {
    function scseed_show_dimensions_column( $column, $post_id ) {
        if ( 'scseed_dimensions' !== $column ) {
            return;
        }
        $meta = wp_get_attachment_metadata( $post_id );
        if ( ! empty( $meta['width'] ) && ! empty( $meta['height'] ) ) {
            echo esc_html( $meta['width'] . ' × ' . $meta['height'] );
        } else {
            echo '&mdash;';
        }
    }
}
add_filter( 'manage_media_columns', 'scseed_add_dimensions_column' );
add_action( 'manage_media_custom_column', 'scseed_show_dimensions_column', 10, 2 );