WordPress - Get a first image attachment in post

media-utilties.php

<?php
function prefix_get_first_attachment( $post ) {
    $attachment = get_children(
        array(
            'post_parent'    => $post->ID,
            'post_type'      => 'attachment',
            'post_mime_type' => 'image',
            'order'          => 'DESC',
            'numberposts'    => 1,
        )
    );

    if ( empty( $attachment ) || is_wp_error( $attachment ) ) {
        return false;
    }

    $attachment = current( $attachment );
    
    return $attachment;
}