diff --git a/screening/source/java/ch/systemsx/cisd/openbis/plugin/screening/client/web/client/application/detailviewers/ImageUrlUtils.java b/screening/source/java/ch/systemsx/cisd/openbis/plugin/screening/client/web/client/application/detailviewers/ImageUrlUtils.java
index 54231124c1dcf74a0ebd10f41df27dd0ac25467b..3624e6a9ef6a7909ef7dcd638551e9929a17f66d 100644
--- a/screening/source/java/ch/systemsx/cisd/openbis/plugin/screening/client/web/client/application/detailviewers/ImageUrlUtils.java
+++ b/screening/source/java/ch/systemsx/cisd/openbis/plugin/screening/client/web/client/application/detailviewers/ImageUrlUtils.java
@@ -74,7 +74,8 @@ public class ImageUrlUtils
         methodWithParameters.addParameter("mode", "thumbnail" + width + "x" + height);
 
         String imageURL = methodWithParameters.toString();
-        return URLMethodWithParameters.createEmbededImageHtml(imageURL, linkURL, width, height);
+        // do not specify width to get correct aspect ratio of the original image
+        return URLMethodWithParameters.createEmbededImageHtml(imageURL, linkURL, -1, height);
     }
 
     /** creates a widget which displays the specified URL and adds it to the container */
@@ -106,7 +107,8 @@ public class ImageUrlUtils
         methodWithParameters.addParameter("mode", "thumbnail" + width + "x" + height);
 
         String imageURL = methodWithParameters.toString();
-        return URLMethodWithParameters.createEmbededImageHtml(imageURL, linkURL, width, height);
+        // do not specify width to get correct aspect ratio of the original image
+        return URLMethodWithParameters.createEmbededImageHtml(imageURL, linkURL, -1, height);
     }
 
     private static URLMethodWithParameters createBasicImageURL(String sessionID, WellImages images,