wordpress get fiture image

1if ( has_post_thumbnail()) {
2   $large_image_url = wp_get_attachment_image_src( get_post_thumbnail_id(), 'large');
3   echo '<a href="' . $large_image_url[0] . '">';
4   the_post_thumbnail('thumbnail');
5   echo '</a>';
6}
7

1<?php if (has_post_thumbnail( $post->ID ) ): ?>
2  <?php $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'single-post-thumbnail' ); ?>
3  <div id="custom-bg" style="background-image: url('<?php echo $image[0]; ?>')">
4
5  </div>
6<?php endif; ?>

1<?php
2	echo get_the_post_thumbnail( $post_id, 'thumbnail' );
3?>