diff --git a/Backend/services/core/src/main/java/org/edu_sharing/repository/server/jobs/helper/NodeCustomClasses.java b/Backend/services/core/src/main/java/org/edu_sharing/repository/server/jobs/helper/NodeCustomClasses.java
new file mode 100644
index 0000000000..f177d52c2c
--- /dev/null
+++ b/Backend/services/core/src/main/java/org/edu_sharing/repository/server/jobs/helper/NodeCustomClasses.java
@@ -0,0 +1,51 @@
+package org.edu_sharing.repository.server.jobs.helper;
+
+import org.alfresco.service.cmr.repository.NodeRef;
+import org.alfresco.service.cmr.repository.StoreRef;
+import org.apache.log4j.Logger;
+import org.edu_sharing.repository.client.tools.CCConstants;
+import org.edu_sharing.repository.server.jobs.quartz.BulkEditNodesJob;
+import org.edu_sharing.repository.server.tools.HttpQueryTool;
+import org.edu_sharing.service.nodeservice.NodeServiceFactory;
+import org.edu_sharing.service.nodeservice.NodeServiceHelper;
+
+import java.io.InputStream;
+import java.util.function.Consumer;
+
+/**
+ * to be used with @BulkEditNodesJob
+ */
+public class NodeCustomClasses {
+    public static class ImportExternalThumbnail implements Consumer<NodeRef> {
+        @Override
+        public void accept(NodeRef nodeRef) {
+            String thumbUrl = NodeServiceHelper.getProperty(nodeRef, CCConstants.CCM_PROP_IO_THUMBNAILURL);
+            if (thumbUrl == null) {
+                Logger.getLogger(BulkEditNodesJob.class).info(nodeRef + " has no " + CCConstants.CCM_PROP_IO_THUMBNAILURL + ", skipping...");
+                return;
+            }
+            try {
+                HttpQueryTool.Callback<Throwable> callback = new HttpQueryTool.Callback<Throwable>() {
+                    @Override
+                    public void handle(InputStream is) {
+                        try {
+                            NodeServiceFactory.getLocalService().writeContent(StoreRef.STORE_REF_WORKSPACE_SPACESSTORE, nodeRef.getId(), is,
+                                    "image/jpeg", null, CCConstants.CCM_PROP_IO_USERDEFINED_PREVIEW);
+                        } catch (Exception e) {
+                            Logger.getLogger(BulkEditNodesJob.class).warn("Thumb fetching failed for " + nodeRef + " " + thumbUrl);
+                        }
+                    }
+                };
+                new HttpQueryTool().queryStream(thumbUrl, callback);
+                if (callback.getResult() != null) {
+                    Logger.getLogger(BulkEditNodesJob.class).warn("Thumb fetching failed for " + nodeRef + " " + thumbUrl + ": " + callback.getResult());
+                } else {
+                    NodeServiceHelper.removeProperty(nodeRef, CCConstants.CCM_PROP_IO_THUMBNAILURL);
+                    Logger.getLogger(BulkEditNodesJob.class).info(nodeRef + " thumb imported: " + thumbUrl);
+                }
+            } catch (Throwable t) {
+                Logger.getLogger(BulkEditNodesJob.class).warn("Thumb fetching failed for " + nodeRef + " " + thumbUrl);
+            }
+        }
+    }
+}
diff --git a/Backend/services/core/src/main/java/org/edu_sharing/service/nodeservice/NodeServiceImpl.java b/Backend/services/core/src/main/java/org/edu_sharing/service/nodeservice/NodeServiceImpl.java
index 3fe43489ef..315e2ca86c 100644
--- a/Backend/services/core/src/main/java/org/edu_sharing/service/nodeservice/NodeServiceImpl.java
+++ b/Backend/services/core/src/main/java/org/edu_sharing/service/nodeservice/NodeServiceImpl.java
@@ -708,7 +708,9 @@ public void updateNodeNative(StoreRef store, String nodeId, Map<String, ?> _prop
 					logger.warn("Error while calling interceptor " + i.getClass().getName() + ": " + e.toString());
 				}
 			}
-			Map<QName, Serializable> propsStore = propsFinal.entrySet().stream().collect(
+			Map<QName, Serializable> propsStore = propsFinal.entrySet().stream().
+					filter(e -> e.getValue() != null).
+					collect(
 					HashMap::new,
 					(m,entry)-> m.put(QName.createQName(entry.getKey()), (Serializable) entry.getValue()),
 					HashMap::putAll