diff --git a/PIL/GifImagePlugin.py b/PIL/GifImagePlugin.py
index a8461f753..443d4db12 100644
--- a/PIL/GifImagePlugin.py
+++ b/PIL/GifImagePlugin.py
@@ -324,7 +324,7 @@ def _save_netpbm(im, fp, filename):
 # --------------------------------------------------------------------
 # GIF utilities
 
-def getheader(im, palette, info=None):
+def getheader(im, palette=None, info=None):
     """Return a list of strings representing a GIF header"""
 
     optimize = info and info.get("optimize", 0)
@@ -352,7 +352,7 @@ def getheader(im, palette, info=None):
     # global palette
     if im.mode == "P":
         # colour palette
-        if palette is not None and Image.isBytesType(palette):
+        if palette is not None and isinstance(palette, bytes):
             paletteBytes = palette
         else:
             paletteBytes =im.im.getpalette("RGB")[:maxcolor*3]
diff --git a/PIL/ImageFile.py b/PIL/ImageFile.py
index 688c33a1d..3b60c0d05 100644
--- a/PIL/ImageFile.py
+++ b/PIL/ImageFile.py
@@ -226,9 +226,8 @@ class ImageFile(Image.Image):
 
         self.fp = None # might be shared
 
-        if not LOAD_TRUNCATED_IMAGES and not self.map and e < 0:
-            # Note: If loading a truncated image results in an all black Image,
-            # the decoder wasn't able to decode anything.
+        if (t == 0 or not LOAD_TRUNCATED_IMAGES) and not self.map and e < 0:
+            # still raised if decoder fails to return anything
             raise_ioerror(e)
 
         # post processing
diff --git a/PIL/JpegImagePlugin.py b/PIL/JpegImagePlugin.py
index 3416711a4..decf04657 100644
--- a/PIL/JpegImagePlugin.py
+++ b/PIL/JpegImagePlugin.py
@@ -465,7 +465,7 @@ def _save(im, fp, filename):
         dpi[0], dpi[1],
         subsampling,
         extra,
-        info.get("exif", "")
+        info.get("exif", b"")
         )
 
     ImageFile._save(im, fp, [("jpeg", (0,0)+im.size, 0, rawmode)])
diff --git a/encode.c b/encode.c
index 4f5902e5b..f355f99d0 100644
--- a/encode.c
+++ b/encode.c
@@ -525,7 +525,7 @@ PyImaging_JpegEncoderNew(PyObject* self, PyObject* args)
     char* rawExif = NULL;
     int rawExifLen = 0;
 
-    if (!PyArg_ParseTuple(args, "ss|iiiiiiii"PY_ARG_BYTES_LENGTH,
+    if (!PyArg_ParseTuple(args, "ss|iiiiiiii"PY_ARG_BYTES_LENGTH""PY_ARG_BYTES_LENGTH,
                           &mode, &rawmode, &quality,
                           &progressive, &smooth, &optimize, &streamtype,
                           &xdpi, &ydpi, &subsampling, &extra, &extra_size,
diff --git a/py3.h b/py3.h
index bee457e06..85979c81c 100644
--- a/py3.h
+++ b/py3.h
@@ -11,7 +11,7 @@
 */
 
 #if PY_VERSION_HEX >= 0x03000000
-#define PY_ARG_BYTES_LENGTH             "y#y#"
+#define PY_ARG_BYTES_LENGTH             "y#"
 
 /* Map PyInt -> PyLong */
 #define PyInt_AsLong                PyLong_AsLong
@@ -20,7 +20,7 @@
 #define PyInt_AS_LONG               PyLong_AS_LONG
 
 #else   /* PY_VERSION_HEX < 0x03000000 */
-#define PY_ARG_BYTES_LENGTH             "s#s#"
+#define PY_ARG_BYTES_LENGTH             "s#"
 
 #if !defined(KEEP_PY_UNICODE)
 /* Map PyUnicode -> PyString */