diff --git a/src/PIL/FtexImagePlugin.py b/src/PIL/FtexImagePlugin.py
index 26e5bd4a6..d60e75bb6 100644
--- a/src/PIL/FtexImagePlugin.py
+++ b/src/PIL/FtexImagePlugin.py
@@ -79,8 +79,6 @@ class FtexImageFile(ImageFile.ImageFile):
         self._size = struct.unpack("<2i", self.fp.read(8))
         mipmap_count, format_count = struct.unpack("<2i", self.fp.read(8))
 
-        self._mode = "RGB"
-
         # Only support single-format files.
         # I don't know of any multi-format file.
         assert format_count == 1
@@ -95,6 +93,7 @@ class FtexImageFile(ImageFile.ImageFile):
             self._mode = "RGBA"
             self.tile = [ImageFile._Tile("bcn", (0, 0) + self.size, 0, (1,))]
         elif format == Format.UNCOMPRESSED:
+            self._mode = "RGB"
             self.tile = [ImageFile._Tile("raw", (0, 0) + self.size, 0, "RGB")]
         else:
             msg = f"Invalid texture compression format: {repr(format)}"