Added support for RGBA PSD images

Tests/test_file_psd.py

@@ -4,7 +4,7 @@
 
 from PIL import Image, PsdImagePlugin
 
-from .helper import assert_image_similar, hopper, is_pypy
+from .helper import assert_image_equal_tofile, assert_image_similar, hopper, is_pypy
 
 test_file = "Tests/images/hopper.psd"
 
@@ -107,6 +107,11 @@ def test_open_after_exclusive_load():
         im.load()
 
 
+def test_rgba():
+    with Image.open("Tests/images/rgba.psd") as im:
+        assert_image_equal_tofile(im, "Tests/images/imagedraw_square.png")
+
+
 def test_icc_profile():
     with Image.open(test_file) as im:
         assert "icc_profile" in im.info

src/PIL/PsdImagePlugin.py

@@ -75,6 +75,9 @@ def _open(self):
 
         if channels > psd_channels:
             raise OSError("not enough channels")
+        if mode == "RGB" and psd_channels == 4:
+            mode = "RGBA"
+            channels = 4
 
         self.mode = mode
         self._size = i32(s, 18), i32(s, 14)