diff --git a/src/PIL/ImImagePlugin.py b/src/PIL/ImImagePlugin.py
index 4613e40b6..6463572f5 100644
--- a/src/PIL/ImImagePlugin.py
+++ b/src/PIL/ImImagePlugin.py
@@ -78,7 +78,7 @@ OPEN = {
     "LA image": ("LA", "LA;L"),
     "PA image": ("LA", "PA;L"),
     "RGBA image": ("RGBA", "RGBA;L"),
-    "RGBX image": ("RGBX", "RGBX;L"),
+    "RGBX image": ("RGB", "RGBX;L"),
     "CMYK image": ("CMYK", "CMYK;L"),
     "YCC image": ("YCbCr", "YCbCr;L"),
 }
diff --git a/src/PIL/TiffImagePlugin.py b/src/PIL/TiffImagePlugin.py
index 10ac9ea3a..e37140590 100644
--- a/src/PIL/TiffImagePlugin.py
+++ b/src/PIL/TiffImagePlugin.py
@@ -200,12 +200,12 @@ OPEN_INFO = {
     (MM, 2, (1,), 2, (8, 8, 8), ()): ("RGB", "RGB;R"),
     (II, 2, (1,), 1, (8, 8, 8, 8), ()): ("RGBA", "RGBA"),  # missing ExtraSamples
     (MM, 2, (1,), 1, (8, 8, 8, 8), ()): ("RGBA", "RGBA"),  # missing ExtraSamples
-    (II, 2, (1,), 1, (8, 8, 8, 8), (0,)): ("RGBX", "RGBX"),
-    (MM, 2, (1,), 1, (8, 8, 8, 8), (0,)): ("RGBX", "RGBX"),
-    (II, 2, (1,), 1, (8, 8, 8, 8, 8), (0, 0)): ("RGBX", "RGBXX"),
-    (MM, 2, (1,), 1, (8, 8, 8, 8, 8), (0, 0)): ("RGBX", "RGBXX"),
-    (II, 2, (1,), 1, (8, 8, 8, 8, 8, 8), (0, 0, 0)): ("RGBX", "RGBXXX"),
-    (MM, 2, (1,), 1, (8, 8, 8, 8, 8, 8), (0, 0, 0)): ("RGBX", "RGBXXX"),
+    (II, 2, (1,), 1, (8, 8, 8, 8), (0,)): ("RGB", "RGBX"),
+    (MM, 2, (1,), 1, (8, 8, 8, 8), (0,)): ("RGB", "RGBX"),
+    (II, 2, (1,), 1, (8, 8, 8, 8, 8), (0, 0)): ("RGB", "RGBXX"),
+    (MM, 2, (1,), 1, (8, 8, 8, 8, 8), (0, 0)): ("RGB", "RGBXX"),
+    (II, 2, (1,), 1, (8, 8, 8, 8, 8, 8), (0, 0, 0)): ("RGB", "RGBXXX"),
+    (MM, 2, (1,), 1, (8, 8, 8, 8, 8, 8), (0, 0, 0)): ("RGB", "RGBXXX"),
     (II, 2, (1,), 1, (8, 8, 8, 8), (1,)): ("RGBA", "RGBa"),
     (MM, 2, (1,), 1, (8, 8, 8, 8), (1,)): ("RGBA", "RGBa"),
     (II, 2, (1,), 1, (8, 8, 8, 8, 8), (1, 0)): ("RGBA", "RGBaX"),
@@ -224,8 +224,8 @@ OPEN_INFO = {
     (MM, 2, (1,), 1, (16, 16, 16), ()): ("RGB", "RGB;16B"),
     (II, 2, (1,), 1, (16, 16, 16, 16), ()): ("RGBA", "RGBA;16L"),
     (MM, 2, (1,), 1, (16, 16, 16, 16), ()): ("RGBA", "RGBA;16B"),
-    (II, 2, (1,), 1, (16, 16, 16, 16), (0,)): ("RGBX", "RGBX;16L"),
-    (MM, 2, (1,), 1, (16, 16, 16, 16), (0,)): ("RGBX", "RGBX;16B"),
+    (II, 2, (1,), 1, (16, 16, 16, 16), (0,)): ("RGB", "RGBX;16L"),
+    (MM, 2, (1,), 1, (16, 16, 16, 16), (0,)): ("RGB", "RGBX;16B"),
     (II, 2, (1,), 1, (16, 16, 16, 16), (1,)): ("RGBA", "RGBa;16L"),
     (MM, 2, (1,), 1, (16, 16, 16, 16), (1,)): ("RGBA", "RGBa;16B"),
     (II, 2, (1,), 1, (16, 16, 16, 16), (2,)): ("RGBA", "RGBA;16L"),
diff --git a/src/libImaging/Unpack.c b/src/libImaging/Unpack.c
index a84dc0a6f..f15769c43 100644
--- a/src/libImaging/Unpack.c
+++ b/src/libImaging/Unpack.c
@@ -1599,10 +1599,14 @@ static struct {
     {"RGB", "BGR;15", 16, ImagingUnpackBGR15},
     {"RGB", "RGB;16", 16, ImagingUnpackRGB16},
     {"RGB", "BGR;16", 16, ImagingUnpackBGR16},
+    {"RGB", "RGBX;16L", 64, unpackRGBA16L},
+    {"RGB", "RGBX;16B", 64, unpackRGBA16B},
     {"RGB", "RGB;4B", 16, ImagingUnpackRGB4B},
     {"RGB", "BGR;5", 16, ImagingUnpackBGR15}, /* compat */
     {"RGB", "RGBX", 32, copy4},
     {"RGB", "RGBX;L", 32, unpackRGBAL},
+    {"RGB", "RGBXX", 40, copy4skip1},
+    {"RGB", "RGBXXX", 48, copy4skip2},
     {"RGB", "RGBA;L", 32, unpackRGBAL},
     {"RGB", "RGBA;15", 16, ImagingUnpackRGBA15},
     {"RGB", "BGRX", 32, ImagingUnpackBGRX},