diff --git a/src/PIL/PsdImagePlugin.py b/src/PIL/PsdImagePlugin.py
--- a/src/PIL/PsdImagePlugin.py
+++ b/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)

diff --git a/Tests/images/rgba.psd b/Tests/images/rgba.psd
new file mode 100644
Binary files /dev/null and b/Tests/images/rgba.psd differ
diff --git a/Tests/test_file_psd.py b/Tests/test_file_psd.py
--- a/Tests/test_file_psd.py
+++ b/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

PSD incorrectly loaded
### What did you do?
I opened the TIFF in Pillow and converted it to JPG.
### What did you expect to happen?
The JPG image to look the same as the original TIFF.
### What actually happened?
The converted JPG looks malformed and has messed up colors.
### What are your OS, Python and Pillow versions?

* OS: Linux
* Python: 3.10.5
* Pillow: 9.1.1 (also tested -git)

```python
>>> img = Image.open("3662b8bd397337482862ab1a06bf3366-OA_535_161_17_F_TE.tif")
>>> out_img = img.convert("RGB")
>>> out_img.save("converted.jpg", quality=95)
```
[original image](https://api.collectie.gent/storage/v1/download/3662b8bd397337482862ab1a06bf3366-OA_535_161_17_F_TE.tif) (beware, 274MB)
[converted image](https://api.collectie.gent/storage/v1/download/3a029a4f48b480211286486a6a1f0f0b-transcode-OA_535_161_17_F_TE.jpg)

Is it okay to report this here or should I report this to the appropriate library (libtiff, jpeg-turbo, ?)

Here is the right place to report it - taking a look, your file is actually not a TIFF, but a Photoshop file. The fact that we're not loading it correctly has nothing to do with those other libraries.
@radarhere My bad, I should have checked the mimetype...