An awesome code snippet that I just found in Automattic’s _s Theme:

[php]
/**
* Filter in a link to a content ID attribute for the next/previous image links on image attachment pages
*
* @since _s 1.0
*/
function _s_enhanced_image_navigation( $url, $id ) {
if ( ! is_attachment() && ! wp_attachment_is_image( $id ) )
return $url;

$image = get_post( $id );
if ( $image->post_parent && $image->post_parent != $id )
$url .= ‘#main’;

return $url;
}
add_filter( ‘attachment_link’, ‘_s_enhanced_image_navigation’, 10, 2 );
[/php]

This adds the #main attribute to image attachment links, so that the enduser always sees the attachment instantly and doesn’t have to scroll down. Especially handy in when you click through a post gallery!