WordPress/wp-content/themes/twentyeleven/image.php

<?php
/**
 * Template for displaying image attachments
 *
 * @package WordPress
 * @subpackage Twenty_Eleven
 * @since Twenty Eleven 1.0
 */

get_header(); ?>

		<div id="primary" class="image-attachment">
			<div id="content" role="main">

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

				<nav id="nav-single">
					<h3 class="assistive-text"><?php _e( 'Image navigation', 'twentyeleven' ); ?></h3>
					<span class="nav-previous"><?php previous_image_link( false, __( '&larr; Previous', 'twentyeleven' ) ); ?></span>
					<span class="nav-next"><?php next_image_link( false, __( 'Next &rarr;', 'twentyeleven' ) ); ?></span>
				</nav><!-- #nav-single -->

					<article id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
						<header class="entry-header">
							<h1 class="entry-title"><?php the_title(); ?></h1>

							<div class="entry-meta">
								<?php
									$metadata = wp_get_attachment_metadata();
									printf(
										__( '<span class="meta-prep meta-prep-entry-date">Published </span> <span class="entry-date"><abbr class="published" title="%1$s">%2$s</abbr></span> at <a href="%3$s" title="Link to full-size image">%4$s &times; %5$s</a> in <a href="%6$s" title="Return to %7$s" rel="gallery">%8$s</a>', 'twentyeleven' ),
										esc_attr( get_the_time() ),
										get_the_date(),
										esc_url( wp_get_attachment_url() ),
										$metadata['width'],
										$metadata['height'],
										esc_url( get_permalink( $post->post_parent ) ),
										esc_attr( strip_tags( get_the_title( $post->post_parent ) ) ),
										get_the_title( $post->post_parent )
									);
								?>
								<?php edit_post_link( __( 'Edit', 'twentyeleven' ), '<span class="edit-link">', '</span>' ); ?>
							</div><!-- .entry-meta -->

						</header><!-- .entry-header -->

						<div class="entry-content">

							<div class="entry-attachment">
								<div class="attachment">
<?php
	/*
	 * Grab the IDs of all the image attachments in a gallery so we can get the URL of the next adjacent image in a gallery,
	 * or the first image (if we're looking at the last image in a gallery), or, in a gallery of one, just the link to that image file
	 */
	$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 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, get the URL of the image
	$next_attachment_url = wp_get_attachment_url();
}
?>
									<a href="<?php echo esc_url( $next_attachment_url ); ?>" title="<?php the_title_attribute(); ?>" rel="attachment">
														<?php
														/**
														 * Filter the Twenty Eleven default attachment size.
														 *
														 * @since Twenty Eleven 1.0
														 *
														 * @param int The height and width attachment size dimensions in pixels. Default 848.
														 */
														$attachment_size = apply_filters( 'twentyeleven_attachment_size', 848 );
														echo wp_get_attachment_image( $post->ID, array( $attachment_size, 1024 ) ); // filterable image width with 1024px limit for image height.
									?>
									</a>

									<?php if ( ! empty( $post->post_excerpt ) ) : ?>
									<div class="entry-caption">
										<?php the_excerpt(); ?>
									</div>
									<?php endif; ?>
								</div><!-- .attachment -->

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

							<div class="entry-description">
								<?php the_content(); ?>
								<?php
								wp_link_pages(
									array(
										'before' => '<div class="page-link"><span>' . __( 'Pages:', 'twentyeleven' ) . '</span>',
										'after'  => '</div>',
									)
								);
?>
							</div><!-- .entry-description -->

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

					</article><!-- #post-<?php the_ID(); ?> -->

					<?php comments_template(); ?>

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

			</div><!-- #content -->
		</div><!-- #primary -->

<?php get_footer(); ?>