Index: wp-includes/class-wp-customize-control.php
===================================================================
--- wp-includes/class-wp-customize-control.php	(revision 32564)
+++ wp-includes/class-wp-customize-control.php	(working copy)
@@ -1169,9 +1169,9 @@
 			</div>
 			<div class="actions">
 				<?php /* translators: Hide as in hide header image via the Customizer */ ?>
-				<button type="button"<?php echo $visibility ?> class="button remove"><?php _ex( 'Hide image', 'custom header' ); ?></button>
+				<button type="button"<?php echo $visibility ?> class="button remove" aria-label="<?php _ex( 'Hide header image', 'custom header' ); ?>"><?php _ex( 'Hide image', 'custom header' ); ?></button>
 				<?php /* translators: New as in add new header image via the Customizer */ ?>
-				<button type="button" class="button new"><?php _ex( 'Add new image', 'header image' ); ?></button>
+				<button type="button" class="button new" aria-label="<?php _ex( 'Add new header image', 'header image' ); ?>"><?php _ex( 'Add new image', 'header image' ); ?></button>
 				<div style="clear:both"></div>
 			</div>
 			<div class="choices">