diff --git a/PVE/Storage.pm b/PVE/Storage.pm
index c86d4f4..ff0d944 100755
--- a/PVE/Storage.pm
+++ b/PVE/Storage.pm
@@ -99,7 +99,7 @@ PVE::Storage::Plugin->init();
 
 my $UDEVADM = '/sbin/udevadm';
 
-our $iso_extension_re = qr/\.(?:[Ii][Ss][Oo]|[Ii][Mm][Gg])/;
+our $iso_extension_re = qr/\.(?:iso|img)/i;
 
 #  PVE::Storage utility functions