Index: wp-admin/custom-header.php
===================================================================
--- wp-admin/custom-header.php	(revision 22081)
+++ wp-admin/custom-header.php	(working copy)
@@ -540,7 +540,8 @@
 	?>
 	<p>
 		<label for="choose-from-library-link"><?php _e( 'Or choose an image from your media library:' ); ?></label><br />
-		<a id="choose-from-library-link" class="button thickbox" href="<?php echo esc_url( $image_library_url ); ?>"><?php _e( 'Choose Image' ); ?></a>
+		<a id="choose-from-library-link" class="button thickbox hide-if-no-js" href="<?php echo esc_url( $image_library_url ); ?>"><?php _e( 'Choose Image' ); ?></a>
+		<p class="hide-if-js"><strong><?php _e( 'You need Javascript to choose a header image from the Media Library.' ); ?></strong></p>
 	</p>
 	</form>
 </td>
Index: wp-admin/custom-background.php
===================================================================
--- wp-admin/custom-background.php	(revision 22081)
+++ wp-admin/custom-background.php	(working copy)
@@ -269,7 +269,8 @@
 	?>
 	<p>
 		<label for="choose-from-library-link"><?php _e( 'Or choose an image from your media library:' ); ?></label><br />
-		<a id="choose-from-library-link" class="button thickbox" href="<?php echo esc_url( $image_library_url ); ?>"><?php _e( 'Choose Image' ); ?></a>
+		<a id="choose-from-library-link" class="button thickbox hide-if-no-js" href="<?php echo esc_url( $image_library_url ); ?>"><?php _e( 'Choose Image' ); ?></a>
+		<p class="hide-if-js"><strong><?php _e( 'You need Javascript to choose a background image from the Media Library.' ); ?></strong></p>
 	</p>
 	</form>
 </td>