diff --git a/PIL/XVThumbImagePlugin.py b/PIL/XVThumbImagePlugin.py
index 7686b263d..a7d39ed89 100644
--- a/PIL/XVThumbImagePlugin.py
+++ b/PIL/XVThumbImagePlugin.py
@@ -18,7 +18,7 @@
 #
 
 from . import Image, ImageFile, ImagePalette
-from ._binary import o8
+from ._binary import i8, o8
 
 __version__ = "0.1"
 
@@ -58,7 +58,7 @@ class XVThumbImageFile(ImageFile.ImageFile):
             s = self.fp.readline()
             if not s:
                 raise SyntaxError("Unexpected EOF reading XV thumbnail file")
-            if s[0] != b'#':
+            if i8(s[0]) != 35:  # ie. when not a comment: '#'
                 break
 
         # parse header line (already read)