Index: Lib/email/test/test_email.py
===================================================================
--- Lib/email/test/test_email.py	(revision 88415)
+++ Lib/email/test/test_email.py	(working copy)
@@ -576,6 +576,20 @@
 
 # Test the email.encoders module
 class TestEncoders(unittest.TestCase):
+    def setUp(self):
+        with openfile('PyBanner048.gif', 'rb') as fp:
+            self.bindata = fp.read()
+
+    def test_EncodersEncode_base64(self):
+        mimed = email.mime.image.MIMEImage(self.bindata)
+        base64ed = mimed.get_payload()
+        # uncoment the print for a visual clarification of the problem.
+        #print (base64ed)
+
+        # work out if any line within the string is > 76 chars
+        lines = base64ed.split('\n')
+        self.assertLessEqual(max([ len(x) for x in lines ]), 76)
+
     def test_encode_empty_payload(self):
         eq = self.assertEqual
         msg = Message()
@@ -1127,10 +1141,11 @@
 
     def test_body(self):
         eq = self.assertEqual
-        bytes = b'\xfa\xfb\xfc\xfd\xfe\xff'
-        msg = MIMEApplication(bytes)
-        eq(msg.get_payload(), '+vv8/f7/')
-        eq(msg.get_payload(decode=True), bytes)
+        bytesdata = b'\xfa\xfb\xfc\xfd\xfe\xff'
+        msg = MIMEApplication(bytesdata)
+        # A strip'ed base64 string is still valid and won't change its value.
+        eq(msg.get_payload().strip(), '+vv8/f7/')
+        eq(msg.get_payload(decode=True), bytesdata)
 
 
 
Index: Lib/email/encoders.py
===================================================================
--- Lib/email/encoders.py	(revision 88415)
+++ Lib/email/encoders.py	(working copy)
@@ -12,7 +12,7 @@
     ]
 
 
-from base64 import b64encode as _bencode
+from base64 import encodebytes as _bencode
 from quopri import encodestring as _encodestring