Image navigation

gistfile1.phtml

<?php 
// http://wordpress.org/support/topic/previous_image_link

function mytheme_get_previous_image() {
	$image = mytheme_adjacent_image_link( true );
	
	if ( $image ) : ?>
		<div class="nav-previous odd summary">
			<div class="entry-meta entry-meta-above"><?php _e('Previous Image','sendtheme'); ?></div>
			<div class="entry-image"><?php echo $image; ?></div>
		</div><?php
	endif; 
}

function mytheme_get_next_image() {
	$image = mytheme_adjacent_image_link( false );
	
	if ( $image ) : ?>
		<div class="nav-next even summary">
			<div class="entry-meta entry-meta-above"><?php _e('Next Image','sendtheme'); ?></div>
			<div class="entry-image"><?php echo $image; ?></div>
		</div><?php 
	endif; 
}

function mytheme_adjacent_image_link( $prev = true ) {
	global $post;
	$post = get_post( $post );
	$attachments = array_values( get_children(
		array('post_parent' => $post->post_parent,
		      'post_type' => 'attachment',
		      'post_mime_type' => 'image',
		      'orderby' => 'menu_order ASC, ID ASC'
		)
	) );

	foreach ( $attachments as $k => $attachment )
		if ( $attachment->ID == $post->ID ) :
			break;
		endif;

	$k = $prev ? $k - 1 : $k + 1;

	if ( isset($attachments[$k]) ) :
		return wp_get_attachment_link($attachments[$k]->ID, 'medium', true);
	else :
		return false;
	endif;
}
?>