diff --git a/src/main/java/org/olat/core/gui/components/image/ImageComponent.java b/src/main/java/org/olat/core/gui/components/image/ImageComponent.java
index d0b669657fa4fc50e9a976cfa70a4a80f92764c5..3b7c33220e3d606bbdcef7d6402dcd9b704f0fd1 100644
--- a/src/main/java/org/olat/core/gui/components/image/ImageComponent.java
+++ b/src/main/java/org/olat/core/gui/components/image/ImageComponent.java
@@ -303,6 +303,8 @@ public class ImageComponent extends AbstractComponent implements Disposable {
 	}
 	
 	protected String getSuffix(String contentType) {
+		if(!StringHelper.containsNonWhitespace(contentType)) return null;
+		
 		contentType = contentType.toLowerCase();
 		if(contentType.indexOf("jpg") >= 0 || contentType.indexOf("jpeg") >= 0) {
 			return "jpg";