diff --git a/PIL/Image.py b/PIL/Image.py
index b2b5d2493..8ca8fa6cf 100644
--- a/PIL/Image.py
+++ b/PIL/Image.py
@@ -614,7 +614,11 @@ class Image:
             self.palette.mode = "RGB"
             self.palette.rawmode = None
             if "transparency" in self.info:
-                self.im.putpalettealpha(self.info["transparency"], 0)
+                if self.info["transparency_palette"]:
+                    self.im.putpalettealpha(0, 0, self.info["transparency_palette"])
+                else:
+                    self.im.putpalettealpha(self.info["transparency"], 0)
+
                 self.palette.mode = "RGBA"
         if self.im:
             return self.im.pixel_access(self.readonly)
diff --git a/PIL/PngImagePlugin.py b/PIL/PngImagePlugin.py
index 12d9fe018..887ca02d1 100644
--- a/PIL/PngImagePlugin.py
+++ b/PIL/PngImagePlugin.py
@@ -254,6 +254,7 @@ class PngStream(ChunkStream):
             i = s.find(b"\0")
             if i >= 0:
                 self.im_info["transparency"] = i
+                self.im_info["transparency_palette"] = s
         elif self.im_mode == "L":
             self.im_info["transparency"] = i16(s)
         elif self.im_mode == "RGB":
diff --git a/_imaging.c b/_imaging.c
index 986f221e4..8adbe3b16 100644
--- a/_imaging.c
+++ b/_imaging.c
@@ -733,13 +733,13 @@ _convert(ImagingObject* self, PyObject* args)
 	return NULL;
     if (paletteimage != NULL) {
       if (!PyImaging_Check(paletteimage)) {
-	PyObject_Print((PyObject *)paletteimage, stderr, 0);
-	PyErr_SetString(PyExc_ValueError, "palette argument must be image with mode 'P'");
-	return NULL;
+        PyObject_Print((PyObject *)paletteimage, stderr, 0);
+        PyErr_SetString(PyExc_ValueError, "palette argument must be image with mode 'P'");
+        return NULL;
       }
       if (paletteimage->image->palette == NULL) {
-	PyErr_SetString(PyExc_ValueError, "null palette");
-	return NULL;
+        PyErr_SetString(PyExc_ValueError, "null palette");
+        return NULL;
       }
     }
 
@@ -1407,7 +1407,9 @@ _putpalettealpha(ImagingObject* self, PyObject* args)
 {
     int index;
     int alpha = 0;
-    if (!PyArg_ParseTuple(args, "i|i", &index, &alpha))
+    char* tpalette = NULL;
+    int tpaletteSize = 0;
+    if (!PyArg_ParseTuple(args, "i|i"PY_ARG_BYTES_LENGTH, &index, &alpha, &tpalette, &tpaletteSize))
 	return NULL;
 
     if (!self->image->palette) {
@@ -1419,9 +1421,17 @@ _putpalettealpha(ImagingObject* self, PyObject* args)
 	PyErr_SetString(PyExc_ValueError, outside_palette);
 	return NULL;
     }
-
+    
     strcpy(self->image->palette->mode, "RGBA");
-    self->image->palette->palette[index*4+3] = (UINT8) alpha;
+
+    if (tpaletteSize > 0) {
+        for (index = 0; index < tpaletteSize; index++) {
+            self->image->palette->palette[index*4+3] = (UINT8) tpalette[index];
+        }
+    }
+    else {
+        self->image->palette->palette[index*4+3] = (UINT8) alpha;
+    }
 
     Py_INCREF(Py_None);
     return Py_None;
@@ -3391,3 +3401,4 @@ init_imaging(void)
 }
 #endif
 
+
diff --git a/selftest.py b/selftest.py
index b6d7a300c..1d490f197 100644
--- a/selftest.py
+++ b/selftest.py
@@ -157,7 +157,7 @@ def testimage():
 
 def check_module(feature, module):
     try:
-        __import__("PIL." + module)
+        __import__(module)
     except ImportError:
         print("***", feature, "support not installed")
     else: