diff --git a/src/main/java/de/thm/arsnova/ImageUtils.java b/src/main/java/de/thm/arsnova/ImageUtils.java
index 111e6c1f09df79cf9809ab8707c8a7f87e7caf5f..51af7e112f02efd2b46077d799bfa8560f54b194 100644
--- a/src/main/java/de/thm/arsnova/ImageUtils.java
+++ b/src/main/java/de/thm/arsnova/ImageUtils.java
@@ -230,11 +230,9 @@ public class ImageUtils {
 	 * @return The <code>byte[]</code> of the image on success, otherwise <code>null</code>.
 	 */
 	byte[] convertFileToByteArray(final String imageUrl) {
-		try {
-			final URL url = new URL(imageUrl);
+		try (InputStream is = new URL(imageUrl).openStream()) {
 			final ByteArrayOutputStream baos = new ByteArrayOutputStream();
 
-			final InputStream is = url.openStream();
 			final byte[] byteChunk = new byte[CHUNK_SIZE];
 			int n;