diff --git a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-imageviewer.tt b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-imageviewer.tt
index 4bc57d82b6..107c6b5f14 100644
--- a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-imageviewer.tt
+++ b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-imageviewer.tt
@@ -87,7 +87,7 @@
                                 <div class="col-lg-3">
                                     <div id="thumbnails">
                                         [% FOREACH image IN images %]
-                                            <a class="cover_thumbnail" data-imagenumber="[% image.imagenumber| html %]" href="/cgi-bin/koha/opac-imageviewer.pl?biblionumber=[% biblionumber | url %]&amp;imagenumber=[% image.imagenumber| uri %]">
+                                            <a class="cover_thumbnail" data-imagenumber="[% image.imagenumber| html %]" href="#">
                                             [% IF loop.first %]
                                                 <img class="thumbnail selected" id="[% image.imagenumber| html %]" src="/cgi-bin/koha/opac-image.pl?imagenumber=[% image.imagenumber | html %]&amp;thumbnail=1" alt="Thumbnail"/>
                                             [% ELSE %]
@@ -114,11 +114,7 @@
             $("#largeCoverImg").attr("src","[% interface | html %]/[% theme | html %]/images/loading.gif");
             showCover([% imagenumber | html %]);
             $("a.cover_thumbnail").on('click',function(){
-                let imagenumber = this.dataset.imagenumber;
-                if (imagenumber){
-                    showCover(imagenumber);
-                }
-                return false;
+                showCover(this.dataset.imagenumber);
             });
         });