WordPress/wp-content/themes/twentyten/loop-attachment.php

<?php
/**
 * The loop that displays an attachment
 *
 * The loop displays the posts and the post content. See
 * https://codex.wordpress.org/The_Loop to understand it and
 * https://codex.wordpress.org/Template_Tags to understand
 * the tags used in it.
 *
 * This can be overridden in child themes with loop-attachment.php.
 *
 * @package WordPress
 * @subpackage Twenty_Ten
 * @since Twenty Ten 1.2
 */
?>

<?php
if ( have_posts() ) {
	while ( have_posts() ) :
		the_post();
	?>

				<?php if ( ! empty( $post->post_parent ) ) : ?>
					<p class="page-title"><a href="<?php echo esc_url( get_permalink( $post->post_parent ) ); ?>" title="<?php echo esc_attr( sprintf( __( 'Return to %s', 'twentyten' ), strip_tags( get_the_title( $post->post_parent ) ) ) ); ?>" rel="gallery">
																<?php
																/* translators: %s - title of parent post */
																printf( __( '<span class="meta-nav">&larr;</span> %s', 'twentyten' ), get_the_title( $post->post_parent ) );
					?>
					</a></p>
				<?php endif; ?>

					<div id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
					<h2 class="entry-title"><?php the_title(); ?></h2>

					<div class="entry-meta">
						<?php
							printf(
								__( '<span class="%1$s">By</span> %2$s', 'twentyten' ),
								'meta-prep meta-prep-author',
								sprintf(
									'<span class="author vcard"><a class="url fn n" href="%1$s" title="%2$s" rel="author">%3$s</a></span>',
									get_author_posts_url( get_the_author_meta( 'ID' ) ),
									esc_attr( sprintf( __( 'View all posts by %s', 'twentyten' ), get_the_author() ) ),
									get_the_author()
								)
							);
							?>
							<span class="meta-sep">|</span>
							<?php
							printf(
								__( '<span class="%1$s">Published</span> %2$s', 'twentyten' ),
								'meta-prep meta-prep-entry-date',
								sprintf(
									'<span class="entry-date"><abbr class="published" title="%1$s">%2$s</abbr></span>',
									esc_attr( get_the_time() ),
									get_the_date()
								)
							);
							if ( wp_attachment_is_image() ) {
								echo ' <span class="meta-sep">|</span> ';
								$metadata = wp_get_attachment_metadata();
								printf(
									__( 'Full size is %s pixels', 'twentyten' ),
									sprintf(
										'<a href="%1$s" title="%2$s">%3$s &times; %4$s</a>',
										esc_url( wp_get_attachment_url() ),
										esc_attr( __( 'Link to full-size image', 'twentyten' ) ),
										$metadata['width'],
										$metadata['height']
									)
								);
							}
							?>
							<?php edit_post_link( __( 'Edit', 'twentyten' ), '<span class="meta-sep">|</span> <span class="edit-link">', '</span>' ); ?>
						</div><!-- .entry-meta -->

						<div class="entry-content">
						<div class="entry-attachment">
	<?php
	if ( wp_attachment_is_image() ) :
		$attachments = array_values(
			get_children(
				array(
					'post_parent'    => $post->post_parent,
					'post_status'    => 'inherit',
					'post_type'      => 'attachment',
					'post_mime_type' => 'image',
					'order'          => 'ASC',
					'orderby'        => 'menu_order ID',
				)
			)
		);
		foreach ( $attachments as $k => $attachment ) {
			if ( $attachment->ID == $post->ID ) {
				break;
			}
		}

		// If there is more than 1 image attachment in a gallery
		if ( count( $attachments ) > 1 ) {
			$k++;
			if ( isset( $attachments[ $k ] ) ) {
				// get the URL of the next image attachment
				$next_attachment_url = get_attachment_link( $attachments[ $k ]->ID );
			} else {          // or get the URL of the first image attachment
				$next_attachment_url = get_attachment_link( $attachments[0]->ID );
			}
		} else {
			// or, if there's only 1 image attachment, get the URL of the image
			$next_attachment_url = wp_get_attachment_url();
		}
	?>
						<p class="attachment"><a href="<?php echo esc_url( $next_attachment_url ); ?>" title="<?php the_title_attribute(); ?>" rel="attachment">
																	<?php
																	/**
																	 * Filter the Twenty Ten default attachment width.
																	 *
																	 * @since Twenty Ten 1.0
																	 *
																	 * @param int The default attachment width in pixels. Default 900.
																	 */
																	$attachment_width = apply_filters( 'twentyten_attachment_size', 900 );
																	/**
																	 * Filter the Twenty Ten default attachment height.
																	 *
																	 * @since Twenty Ten 1.0
																	 *
																	 * @param int The default attachment height in pixels. Default 900.
																	 */
																	$attachment_height = apply_filters( 'twentyten_attachment_height', 900 );
																	echo wp_get_attachment_image( $post->ID, array( $attachment_width, $attachment_height ) ); // filterable image width with, essentially, no limit for image height.
							?>
							</a></p>

							<div id="nav-below" class="navigation">
							<div class="nav-previous"><?php previous_image_link( false ); ?></div>
							<div class="nav-next"><?php next_image_link( false ); ?></div>
						</div><!-- #nav-below -->
	<?php else : ?>
						<a href="<?php echo esc_url( wp_get_attachment_url() ); ?>" title="<?php the_title_attribute(); ?>" rel="attachment"><?php echo esc_html( basename( get_permalink() ) ); ?></a>
	<?php endif; ?>
						</div><!-- .entry-attachment -->
						<div class="entry-caption">
						<?php
						if ( ! empty( $post->post_excerpt ) ) {
							the_excerpt();}
?>
</div>

	<?php the_content( __( 'Continue reading <span class="meta-nav">&rarr;</span>', 'twentyten' ) ); ?>
	<?php
	wp_link_pages(
		array(
			'before' => '<div class="page-link">' . __( 'Pages:', 'twentyten' ),
			'after'  => '</div>',
		)
	);
	?>

					</div><!-- .entry-content -->

					<div class="entry-utility">
						<?php twentyten_posted_in(); ?>
						<?php edit_post_link( __( 'Edit', 'twentyten' ), ' <span class="edit-link">', '</span>' ); ?>
					</div><!-- .entry-utility -->
				</div><!-- #post-## -->

<?php comments_template(); ?>

<?php endwhile;
}; // end of the loop. ?>