diff --git a/src/main/java/de/thm/arsnova/ImageUtils.java b/src/main/java/de/thm/arsnova/ImageUtils.java
index 3c8cf374f35957aa263be380a955ccad1775f224..80afc2e10414cc4a94ae21809ddaa091d503e459 100644
--- a/src/main/java/de/thm/arsnova/ImageUtils.java
+++ b/src/main/java/de/thm/arsnova/ImageUtils.java
@@ -140,7 +140,9 @@ public class ImageUtils {
 				output.flush();
 				output.close();
 				
-				return Base64.encodeBase64String(output.toByteArray());
+				result.append(Base64.encodeBase64String(output.toByteArray()));
+				
+				return result.toString();
 			} catch (IOException e) {
 				LOGGER.error(e.getLocalizedMessage());
 				return null;