diff --git a/typo3/sysext/backend/Classes/View/ThumbnailView.php b/typo3/sysext/backend/Classes/View/ThumbnailView.php
index 9a63f5e1e7b72995908f76f7d3e8ba86c88d790d..66b18b65917fa4c2515d38ecc8b1ea75857735e9 100644
--- a/typo3/sysext/backend/Classes/View/ThumbnailView.php
+++ b/typo3/sysext/backend/Classes/View/ThumbnailView.php
@@ -196,6 +196,8 @@ class ThumbnailView {
 	 * @todo Define visibility
 	 */
 	public function main() {
+		// Clean output buffer to ensure no extraneous output exists
+		ob_clean();
 		// If file exists, we make a thumbnail of the file.
 		if (is_object($this->image)) {
 			// Check file extension: