diff --git a/docs/handbook/writing-your-own-file-decoder.rst b/docs/handbook/writing-your-own-file-decoder.rst
index f3f34e30d..0763109ab 100644
--- a/docs/handbook/writing-your-own-file-decoder.rst
+++ b/docs/handbook/writing-your-own-file-decoder.rst
@@ -201,7 +201,8 @@ table describes some commonly used **raw modes**:
 +-----------+-----------------------------------------------------------------+
 | ``BGR``   | 24-bit true colour, stored as (blue, green, red).               |
 +-----------+-----------------------------------------------------------------+
-| ``RGBX``  | 24-bit true colour, stored as (red, green, blue, pad).          |
+| ``RGBX``  | 24-bit true colour, stored as (red, green, blue, pad). The pad  |
+|           | pixels may vary.                                                |
 +-----------+-----------------------------------------------------------------+
 | ``RGB;L`` | 24-bit true colour, line interleaved (first all red pixels, then|
 |           | all green pixels, finally all blue pixels).                     |
diff --git a/src/libImaging/Unpack.c b/src/libImaging/Unpack.c
index 02196d255..ff0df861c 100644
--- a/src/libImaging/Unpack.c
+++ b/src/libImaging/Unpack.c
@@ -1333,7 +1333,7 @@ static struct {
     {"RGB",     "RGBX;L",       32,     unpackRGBAL},
     {"RGB",     "RGBA;L",       32,     unpackRGBAL},
     {"RGB",     "BGRX",         32,     ImagingUnpackBGRX},
-    {"RGB",     "XRGB",         24,     ImagingUnpackXRGB},
+    {"RGB",     "XRGB",         32,     ImagingUnpackXRGB},
     {"RGB",     "XBGR",         32,     ImagingUnpackXBGR},
     {"RGB",     "YCC;P",        24,     ImagingUnpackYCC},
     {"RGB",     "R",            8,      band0},
@@ -1403,7 +1403,7 @@ static struct {
     {"RGBX",    "RGBX;16L",     64,     unpackRGBA16L},
     {"RGBX",    "RGBX;16B",     64,     unpackRGBA16B},
     {"RGBX",    "BGRX",         32,     ImagingUnpackBGRX},
-    {"RGBX",    "XRGB",         24,     ImagingUnpackXRGB},
+    {"RGBX",    "XRGB",         32,     ImagingUnpackXRGB},
     {"RGBX",    "XBGR",         32,     ImagingUnpackXBGR},
     {"RGBX",    "YCC;P",        24,     ImagingUnpackYCC},
     {"RGBX",    "R",            8,      band0},