diff --git a/plone/app/event/portlets/portlet_events.pt b/plone/app/event/portlets/portlet_events.pt
index e6aa5cdec..726439429 100644
--- a/plone/app/event/portlets/portlet_events.pt
+++ b/plone/app/event/portlets/portlet_events.pt
@@ -30,7 +30,7 @@
                             title item_descr"
             tal:define="scale item/context/@@images|nothing;">
           <span tal:condition="item_hasimage">
-              <img tal:define="img_tag python:scale.scale('image', scale=thumb_scale).tag(css_class='pull-right image-'+thumb_scale)"
+              <img tal:define="img_tag python:scale.scale('image', scale=thumb_scale).tag(css_class='pull-right thumb-'+thumb_scale)"
                    tal:replace="structure img_tag" />
           </span>
           <span tal:replace="item_title">Some Event</span>