windowscodecs: Add support for generating WICBitmapPaletteTypeFixedGray4 palette.
diff --git a/dlls/windowscodecs/palette.c b/dlls/windowscodecs/palette.c
index 8941fb5..ffd5877 100644
--- a/dlls/windowscodecs/palette.c
+++ b/dlls/windowscodecs/palette.c
@@ -117,6 +117,16 @@
         colors[1] = 0xffffffff;
         break;
 
+    case WICBitmapPaletteTypeFixedGray4:
+        count = 4;
+        colors = HeapAlloc(GetProcessHeap(), 0, count * sizeof(WICColor));
+        if (!colors) return E_OUTOFMEMORY;
+        colors[0] = 0xff000000;
+        colors[1] = 0xff555555;
+        colors[2] = 0xffaaaaaa;
+        colors[3] = 0xffffffff;
+        break;
+
     default:
         FIXME("(%p,%u,%d): stub\n", iface, type, add_transparent);
         return E_NOTIMPL;
diff --git a/dlls/windowscodecs/tests/palette.c b/dlls/windowscodecs/tests/palette.c
index 7a34be7..1768e1a 100644
--- a/dlls/windowscodecs/tests/palette.c
+++ b/dlls/windowscodecs/tests/palette.c
@@ -159,6 +159,8 @@
     } td[] =
     {
         { WICBitmapPaletteTypeFixedBW, 1, 1, 2, { 0xff000000, 0xffffffff } },
+        { WICBitmapPaletteTypeFixedGray4, 0, 1, 4,
+          { 0xff000000, 0xff555555, 0xffaaaaaa, 0xffffffff } },
     };
     IWICImagingFactory *factory;
     IWICPalette *palette;