--- a/MacOSXIconReader.st	Fri Oct 18 16:29:06 2019 +0200
+++ b/MacOSXIconReader.st	Fri Oct 18 16:29:10 2019 +0200
@@ -154,7 +154,7 @@
     inStream isNil ifTrue:[^ false].
     someBytes := inStream nextBytes:4.
     inStream close.
-    ^ self hasValidImageHeader:someBytes
+    ^ (someBytes size == 4) and:[self hasValidImageHeader:someBytes]
 ! !
 
 !MacOSXIconReader methodsFor:'image reading'!