diff -r b9dd84d35128 -r 0cdf3652748d src/pyams_portal/portlets/image/zmi/preview.pt
--- a/src/pyams_portal/portlets/image/zmi/preview.pt	Mon Jul 09 11:43:13 2018 +0200
+++ b/src/pyams_portal/portlets/image/zmi/preview.pt	Mon Jul 09 13:42:42 2018 +0200
@@ -3,14 +3,14 @@
 		<a class="fancybox" data-toggle
 		   data-ams-fancybox-type="image"
 		   tal:define="image settings.image;
-					   image_url extension:absolute_url(image);
+					   image_url tales:absolute_url(image);
 					   slot_config view.slot_configuration;
 					   slot_width slot_config.get_width();
 					   base_width 100 / 12;
-					   thumbnails extension:thumbnails(image);
+					   thumbnails tales:thumbnails(image);
 					   target python:thumbnails.get_thumbnail('800x600');
-					   timestamp extension:timestamp(image);"
-		   tal:attributes="href extension:absolute_url(target)">
+					   timestamp tales:timestamp(image);"
+		   tal:attributes="href tales:absolute_url(target)">
 			<picture>
 				<tal:var define="width slot_width['lg']">
 					<source media="(min-width: 1200px)"