diff --git a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-shelves.tt b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-shelves.tt
index 10d452da36..b837bcd8ff 100644
--- a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-shelves.tt
+++ b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-shelves.tt
@@ -751,7 +751,7 @@
     <div class="modal-content">
         <div class="modal-body">
             <div style="margin:1em;padding:1em;font-size:150%;">
-                <img src="[% interface | html %]/[% theme | html %]/images/loading.gif" /> Loading
+                <img src="[% interface | html %]/[% theme | html %]/images/loading.gif" alt="" /> Loading
             </div>
         </div>
     </div>