Fixed check for the jp2 format (Github: #28)
diff --git a/MagickCore/magic.c b/MagickCore/magic.c
index 5d446ee..299e424 100644
--- a/MagickCore/magic.c
+++ b/MagickCore/magic.c
@@ -137,7 +137,7 @@
     { "JPEG", 0, MagicPattern("\377\330\377") },
     { "J2K", 0, MagicPattern("\xff\x4f\xff\x51") },
     { "JPC", 0, MagicPattern("\x0d\x0a\x87\x0a") },
-    { "JP2", 4, MagicPattern("\x00\x00\x00\x0c\x6a\x50\x20\x20\x0d\x0a\x87\x0a") },
+    { "JP2", 0, MagicPattern("\x00\x00\x00\x0c\x6a\x50\x20\x20\x0d\x0a\x87\x0a") },
     { "MAT", 0, MagicPattern("MATLAB 5.0 MAT-file,") },
     { "MIFF", 0, MagicPattern("Id=ImageMagick") },
     { "MIFF", 0, MagicPattern("id=ImageMagick") },