diff --git a/src/main/java/org/gcube/common/storagehubwrapper/server/StorageHubClientService.java b/src/main/java/org/gcube/common/storagehubwrapper/server/StorageHubClientService.java
index b76059c..e1703ca 100644
--- a/src/main/java/org/gcube/common/storagehubwrapper/server/StorageHubClientService.java
+++ b/src/main/java/org/gcube/common/storagehubwrapper/server/StorageHubClientService.java
@@ -1,6 +1,5 @@
 package org.gcube.common.storagehubwrapper.server;
 
-import java.io.ByteArrayInputStream;
 import java.io.InputStream;
 import java.net.URL;
 import java.util.List;
@@ -618,7 +617,7 @@ public class StorageHubClientService {
 	 * @return the thumbnail data
 	 * @throws Exception the exception
 	 */
-	public StreamDescriptor getThumbnailData(String itemId) throws Exception{
+	public byte[] getThumbnailData(String itemId) throws Exception{
 
 		Validate.notNull(itemId, "Bad request of getThumbnailData, the itemId is null");
 		setContextProviders(scope, authorizationToken);
@@ -631,7 +630,7 @@ public class StorageHubClientService {
     		if(thumbBytes==null || thumbBytes.length==0)
     			throw new Exception("Thumbnail Data is not available for image: "+item.getName());
 
-    		return new StreamDescriptor(new ByteArrayInputStream(thumbBytes), item.getName());
+    		return thumbBytes;
 		}else
 			throw new Exception("Thumbnail Data is not available for type: "+item.getClass().getSimpleName());
 	}
diff --git a/src/main/java/org/gcube/common/storagehubwrapper/server/WorkspaceStorageHubClientService.java b/src/main/java/org/gcube/common/storagehubwrapper/server/WorkspaceStorageHubClientService.java
index fd0a9a8..623c2be 100644
--- a/src/main/java/org/gcube/common/storagehubwrapper/server/WorkspaceStorageHubClientService.java
+++ b/src/main/java/org/gcube/common/storagehubwrapper/server/WorkspaceStorageHubClientService.java
@@ -3,6 +3,7 @@
  */
 package org.gcube.common.storagehubwrapper.server;
 
+import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URL;
@@ -652,7 +653,7 @@ public final class WorkspaceStorageHubClientService implements Workspace{
 
 		try {
 			StreamDescriptor streamDesc = storageHubClientService.downloadFile(itemId, versionName, nodeIdsToExclude);
-			return new org.gcube.common.storagehubwrapper.shared.tohl.impl.StreamDescriptor(streamDesc.getStream(), streamDesc.getFileName());
+			return new org.gcube.common.storagehubwrapper.shared.tohl.impl.StreamDescriptor(streamDesc.getStream(), streamDesc.getFileName(), null);
 		} catch (Exception e) {
 			logger.error("Error on downloading the file: "+fileName+ " with id: "+itemId, e);
 			String error = e.getMessage()!=null?e.getMessage():"";
@@ -676,7 +677,7 @@ public final class WorkspaceStorageHubClientService implements Workspace{
 
 		try {
 			StreamDescriptor streamDesc = storageHubClientService.downloadFolder(folderId, nodeIdsToExclude);
-			return new org.gcube.common.storagehubwrapper.shared.tohl.impl.StreamDescriptor(streamDesc.getStream(), streamDesc.getFileName());
+			return new org.gcube.common.storagehubwrapper.shared.tohl.impl.StreamDescriptor(streamDesc.getStream(), streamDesc.getFileName(), null);
 		} catch (Exception e) {
 			logger.error("Error on downloading the folder: "+folderName+ " with id: "+folderId, e);
 			String error = e.getMessage()!=null?e.getMessage():"";
@@ -859,11 +860,16 @@ public final class WorkspaceStorageHubClientService implements Workspace{
 		}
 	}
 
-	public StreamDescriptor getThumbnailData(String itemId) throws Exception{
+
+	/* (non-Javadoc)
+	 * @see org.gcube.common.storagehubwrapper.server.tohl.Workspace#getThumbnailData(java.lang.String)
+	 */
+	public ItemStreamDescriptor getThumbnailData(String itemId) throws Exception{
 
 		try{
 
-			return storageHubClientService.getThumbnailData(itemId);
+			byte[] thumbBytes = storageHubClientService.getThumbnailData(itemId);
+			return new org.gcube.common.storagehubwrapper.shared.tohl.impl.StreamDescriptor(new ByteArrayInputStream(thumbBytes), null, new Long(thumbBytes.length));
 
 		}catch(Exception e){
 			logger.error("Error on getThumbnailData for: "+itemId, e);
diff --git a/src/main/java/org/gcube/common/storagehubwrapper/server/tohl/Workspace.java b/src/main/java/org/gcube/common/storagehubwrapper/server/tohl/Workspace.java
index 847a1bb..6c45907 100644
--- a/src/main/java/org/gcube/common/storagehubwrapper/server/tohl/Workspace.java
+++ b/src/main/java/org/gcube/common/storagehubwrapper/server/tohl/Workspace.java
@@ -9,7 +9,6 @@ import java.net.URL;
 import java.util.List;
 import java.util.Map;
 
-import org.gcube.common.storagehub.client.StreamDescriptor;
 import org.gcube.common.storagehub.model.items.Item;
 import org.gcube.common.storagehub.model.types.GenericItemType;
 import org.gcube.common.storagehubwrapper.shared.ACLType;
@@ -302,7 +301,6 @@ public interface Workspace{
 	public List<WorkspaceFileVersion> getListVersionsForFile(String fileItemId) throws Exception;
 
 
-
 	/**
 	 * Gets the thumbnail data.
 	 *
@@ -310,7 +308,7 @@ public interface Workspace{
 	 * @return the thumbnail data
 	 * @throws Exception the exception
 	 */
-	public StreamDescriptor getThumbnailData(String itemId) throws Exception;
+	public ItemStreamDescriptor getThumbnailData(String itemId) throws Exception;
 
 
 
diff --git a/src/main/java/org/gcube/common/storagehubwrapper/shared/tohl/impl/StreamDescriptor.java b/src/main/java/org/gcube/common/storagehubwrapper/shared/tohl/impl/StreamDescriptor.java
index 1f0cacb..28ddee9 100644
--- a/src/main/java/org/gcube/common/storagehubwrapper/shared/tohl/impl/StreamDescriptor.java
+++ b/src/main/java/org/gcube/common/storagehubwrapper/shared/tohl/impl/StreamDescriptor.java
@@ -63,6 +63,7 @@ public class StreamDescriptor implements ItemStreamDescriptor, Serializable{
 	private static final long serialVersionUID = -5482612709953553644L;
 	private InputStream stream;
 	private String itemName;
+	private Long size;
 
 
 }