diff --git a/Tests/test_file_ppm.py b/Tests/test_file_ppm.py
index 47f8b845e..dc239cc4c 100644
--- a/Tests/test_file_ppm.py
+++ b/Tests/test_file_ppm.py
@@ -14,12 +14,14 @@ class TestFilePpm(PillowTestCase):
         self.assertEqual(im.mode, "RGB")
         self.assertEqual(im.size, (128, 128))
         self.assertEqual(im.format, "PPM")
+        self.assertEqual(im.get_format_mimetype(), "image/x-portable-pixmap")
 
     def test_16bit_pgm(self):
         im = Image.open('Tests/images/16_bit_binary.pgm')
         im.load()
         self.assertEqual(im.mode, 'I')
         self.assertEqual(im.size, (20, 100))
+        self.assertEqual(im.get_format_mimetype(), "image/x-portable-graymap")
 
         tgt = Image.open('Tests/images/16_bit_binary_pgm.png')
         self.assert_image_equal(im, tgt)
@@ -49,3 +51,16 @@ class TestFilePpm(PillowTestCase):
 
         with self.assertRaises(IOError):
             Image.open('Tests/images/negative_size.ppm')
+
+    def test_mimetypes(self):
+        path = self.tempfile('temp.pgm')
+
+        with open(path, 'w') as f:
+            f.write("P4\n128 128\n255")
+        im = Image.open(path)
+        self.assertEqual(im.get_format_mimetype(), "image/x-portable-bitmap")
+
+        with open(path, 'w') as f:
+            f.write("PyCMYK\n128 128\n255")
+        im = Image.open(path)
+        self.assertEqual(im.get_format_mimetype(), "image/x-portable-anymap")
diff --git a/src/PIL/PpmImagePlugin.py b/src/PIL/PpmImagePlugin.py
index 750454dc5..e3e411cad 100644
--- a/src/PIL/PpmImagePlugin.py
+++ b/src/PIL/PpmImagePlugin.py
@@ -70,7 +70,14 @@ class PpmImageFile(ImageFile.ImageFile):
         s = self.fp.read(1)
         if s != b"P":
             raise SyntaxError("not a PPM file")
-        mode = MODES[self._token(s)]
+        magic_number = self._token(s)
+        mode = MODES[magic_number]
+
+        self.custom_mimetype = {
+            b"P4": "image/x-portable-bitmap",
+            b"P5": "image/x-portable-graymap",
+            b"P6": "image/x-portable-pixmap",
+        }.get(magic_number)
 
         if mode == "1":
             self.mode = "1"
@@ -158,3 +165,5 @@ Image.register_open(PpmImageFile.format, PpmImageFile, _accept)
 Image.register_save(PpmImageFile.format, _save)
 
 Image.register_extensions(PpmImageFile.format, [".pbm", ".pgm", ".ppm"])
+
+Image.register_mime(PpmImageFile.format, "image/x-portable-anymap")