diff --git a/identify/extensions.py b/identify/extensions.py
index e21b6ab..d8cd295 100644
--- a/identify/extensions.py
+++ b/identify/extensions.py
@@ -267,6 +267,7 @@
 }
 EXTENSIONS_NEED_BINARY_CHECK = {
     'plist': {'plist'},
+    'ppm': {'image', 'ppm'},
 }
 
 NAMES = {