Index: wp-includes/script-loader.php
===================================================================
--- wp-includes/script-loader.php	(revision 19847)
+++ wp-includes/script-loader.php	(working copy)
@@ -165,6 +165,8 @@
 	$scripts->add( 'jquery-hotkeys', "/wp-includes/js/jquery/jquery.hotkeys$suffix.js", array('jquery'), '0.0.2m', 1 );
 	$scripts->add( 'jquery-table-hotkeys', "/wp-includes/js/jquery/jquery.table-hotkeys$suffix.js", array('jquery', 'jquery-hotkeys'), false, 1 );
 
+	$scripts->add( 'jquery-masonry', "/wp-includes/js/jquery.masonry$suffix.js", array('jquery'), '2.1.02', 1 );
+
 	$scripts->add( 'thickbox', "/wp-includes/js/thickbox/thickbox.js", array('jquery'), '3.1-20111117', 1 );
 	$scripts->localize( 'thickbox', 'thickboxL10n', array(
 			'next' => __('Next >'),
Index: wp-admin/custom-header.php
===================================================================
--- wp-admin/custom-header.php	(revision 19847)
+++ wp-admin/custom-header.php	(working copy)
@@ -140,6 +140,8 @@
 	function js_includes() {
 		$step = $this->step();
 
+		if ( 1 == $step )
+			wp_enqueue_script('jquery-masonry');
 		if ( ( 1 == $step || 3 == $step ) && $this->header_text() )
 			wp_enqueue_script('farbtastic');
 		elseif ( 2 == $step )
@@ -637,7 +639,13 @@
 	<?php endif; ?>
 </tbody>
 </table>
-
+<script type="text/javascript">
+jQuery(function() {
+	jQuery('.available-headers').masonry({
+		itemSelector: '.default-header',
+	});
+});
+</script>
 	<?php if ( $this->header_text() ) : ?>
 <table class="form-table">
 <tbody>