diff --git a/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dataaccess/HCSDatasetLoader.java b/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dataaccess/HCSDatasetLoader.java
index f39df57c12d4d19ecd2faa463ad1c586b456960c..478c06adb4afbbc22a2392bd3ee354ab58631fb9 100644
--- a/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dataaccess/HCSDatasetLoader.java
+++ b/screening/source/java/ch/systemsx/cisd/openbis/dss/etl/dataaccess/HCSDatasetLoader.java
@@ -141,9 +141,12 @@ public class HCSDatasetLoader implements IHCSDatasetLoader
                 imageDTO =
                         query.tryGetImage(chosenChannelId, getDataset().getId(), tileLocation,
                                 wellLocation);
-                content =
+                if (imageDTO != null)
+                {
+                    content =
                         new ThumbnailContent(contentRepository.getContent(imageDTO.getFilePath()),
                                 thumbnailSizeOrNull);
+                }
             } else
             {
                 content = contentRepository.getContent(imageDTO.getFilePath());