diff --git a/Tests/test_lib_pack.py b/Tests/test_lib_pack.py
index a66bf9708..09c6214cc 100644
--- a/Tests/test_lib_pack.py
+++ b/Tests/test_lib_pack.py
@@ -63,9 +63,13 @@ def get_pack_parameters() -> UnPackParamTypes:
 
     # Mode RGB
     params += [
+        ("RGB", "XRGB;1555", b"\x00\x86\x01\x8c", [(8, 131, 0), (24, 0, 8)]),
+        ("RGB", "RGB;565", b"\x00\n\x00\x1c", [(8, 64, 0), (24, 129, 0)]),
         ("RGB", "RGB", 3, [(1, 2, 3), (4, 5, 6), (7, 8, 9)]),
         ("RGB", "RGBX", b"\x01\x02\x03\xff\x05\x06\x07\xff", [(1, 2, 3), (5, 6, 7)]),
         ("RGB", "XRGB", b"\x00\x02\x03\x04\x00\x06\x07\x08", [(2, 3, 4), (6, 7, 8)]),
+        ("RGB", "XBGR;1555", b"\x00\x86\x01\x8c", [(0, 131, 8), (8, 0, 24)]),
+        ("RGB", "BGR;565", b"\x00\n\x00\x1c", [(0, 64, 8), (0, 129, 24)]),
         ("RGB", "BGR", 3, [(3, 2, 1), (6, 5, 4), (9, 8, 7)]),
         ("RGB", "BGRX", b"\x01\x02\x03\x00\x05\x06\x07\x00", [(3, 2, 1), (7, 6, 5)]),
         ("RGB", "XBGR", b"\x00\x02\x03\x04\x00\x06\x07\x08", [(4, 3, 2), (8, 7, 6)]),
@@ -322,10 +326,19 @@ def get_unpack_parameters() -> UnPackParamTypes:
         ("RGB", "RGB;16B", 6, [(1, 3, 5), (7, 9, 11)]),
         ("RGB", "BGR", 3, [(3, 2, 1), (6, 5, 4), (9, 8, 7)]),
         ("RGB", "RGB;15", 2, [(8, 131, 0), (24, 0, 8)]),
+        ("RGB", "XRGB;1555", 2, [(0, 132, 8), (8, 0, 24)]),
+        ("RGB", "ARGB;1555", 2, [(0, 132, 8), (8, 0, 24)]),
+        ("RGB", "ARGB;1555Z", 2, [(0, 132, 8), (8, 0, 24)]),
         ("RGB", "BGR;15", 2, [(0, 131, 8), (8, 0, 24)]),
+        ("RGB", "XBGR;1555", 2, [(8, 132, 0), (24, 0, 8)]),
+        ("RGB", "ABGR;1555", 2, [(8, 132, 0), (24, 0, 8)]),
         ("RGB", "RGB;16", 2, [(8, 64, 0), (24, 129, 0)]),
+        ("RGB", "RGB;565", 2, [(0, 65, 8), (0, 130, 24)]),
         ("RGB", "BGR;16", 2, [(0, 64, 8), (0, 129, 24)]),
+        ("RGB", "BGR;565", 2, [(8, 65, 0), (24, 130, 0)]),
         ("RGB", "RGB;4B", 2, [(17, 0, 34), (51, 0, 68)]),
+        ("RGB", "XBGR;4", 2, [(17, 0, 34), (51, 0, 68)]),
+        ("RGB", "ABGR;4", 2, [(17, 0, 34), (51, 0, 68)]),
         ("RGB", "RGBX", 4, [(1, 2, 3), (5, 6, 7), (9, 10, 11)]),
         ("RGB", "RGBX;L", 4, [(1, 4, 7), (2, 5, 8), (3, 6, 9)]),
         ("RGB", "BGRX", 4, [(3, 2, 1), (7, 6, 5), (11, 10, 9)]),
@@ -481,8 +494,12 @@ def get_unpack_parameters() -> UnPackParamTypes:
         ),
         ("RGBA", "RGBA;L", 4, [(1, 4, 7, 10), (2, 5, 8, 11), (3, 6, 9, 12)]),
         ("RGBA", "RGBA;15", 2, [(8, 131, 0, 0), (24, 0, 8, 0)]),
+        ("RGBA", "ARGB;1555", 2, [(0, 132, 8, 0), (8, 0, 24, 0)]),
+        ("RGBA", "ARGB;1555Z", 2, [(0, 132, 8, X), (8, 0, 24, X)]),
         ("RGBA", "BGRA;15", 2, [(0, 131, 8, 0), (8, 0, 24, 0)]),
+        ("RGBA", "ABGR;1555", 2, [(8, 132, 0, 0), (24, 0, 8, 0)]),
         ("RGBA", "RGBA;4B", 2, [(17, 0, 34, 0), (51, 0, 68, 0)]),
+        ("RGBA", "ABGR;4", 2, [(17, 0, 34, 0), (51, 0, 68, 0)]),
         ("RGBA", "RGBA;16L", 8, [(2, 4, 6, 8), (10, 12, 14, 16)]),
         ("RGBA", "RGBA;16B", 8, [(1, 3, 5, 7), (9, 11, 13, 15)]),
         ("RGBA", "BGRA;16L", 8, [(6, 4, 2, 8), (14, 12, 10, 16)]),
@@ -545,8 +562,13 @@ def get_unpack_parameters() -> UnPackParamTypes:
         ("RGBX", "RGB;16B", 6, [(1, 3, 5, X), (7, 9, 11, X)]),
         ("RGBX", "BGR", 3, [(3, 2, 1, X), (6, 5, 4, X), (9, 8, 7, X)]),
         ("RGBX", "RGB;15", 2, [(8, 131, 0, X), (24, 0, 8, X)]),
+        ("RGBX", "XRGB;1555", 2, [(0, 132, 8, X), (8, 0, 24, X)]),
+        ("RGBX", "RGB;565", 2, [(0, 65, 8, X), (0, 130, 24, X)]),
         ("RGBX", "BGR;15", 2, [(0, 131, 8, X), (8, 0, 24, X)]),
+        ("RGBX", "XBGR;1555", 2, [(8, 132, 0, X), (24, 0, 8, X)]),
+        ("RGBX", "BGR;565", 2, [(8, 65, 0, X), (24, 130, 0, X)]),
         ("RGBX", "RGB;4B", 2, [(17, 0, 34, X), (51, 0, 68, X)]),
+        ("RGBX", "XBGR;4", 2, [(17, 0, 34, X), (51, 0, 68, X)]),
         ("RGBX", "RGBX", 4, [(1, 2, 3, 4), (5, 6, 7, 8), (9, 10, 11, 12)]),
         ("RGBX", "RGBXX", 5, [(1, 2, 3, 4), (6, 7, 8, 9), (11, 12, 13, 14)]),
         ("RGBX", "RGBXXX", 6, [(1, 2, 3, 4), (7, 8, 9, 10), (13, 14, 15, 16)]),
diff --git a/src/libImaging/Pack.c b/src/libImaging/Pack.c
index c29473d90..79076c2e8 100644
--- a/src/libImaging/Pack.c
+++ b/src/libImaging/Pack.c
@@ -254,6 +254,30 @@ packLAL(UINT8 *out, const UINT8 *in, int pixels) {
     }
 }
 
+static void
+ImagingPackXRGB1555(UINT8 *out, const UINT8 *in, int pixels) {
+    for (int i = 0; i < pixels; out += 2, in += 4, i++) {
+        /* XRGB, 1/5/5/5 bits per pixel, little-endian */
+        const UINT8 r = in[0] >> 3;
+        const UINT8 g = in[1] >> 3;
+        const UINT8 b = in[2] >> 3;
+        out[1] = 0x80 | (r << 2) | (g >> 3);
+        out[0] = (g << 5) | b;
+    }
+}
+
+static void
+ImagingPackRGB565(UINT8 *out, const UINT8 *in, int pixels) {
+    for (int i = 0; i < pixels; out += 2, in += 4, i++) {
+        /* RGB, 5/6/5 bits per pixel, little-endian */
+        const UINT8 r = in[0] >> 3;
+        const UINT8 g = in[1] >> 2;
+        const UINT8 b = in[2] >> 3;
+        out[1] = (r << 3) | (g >> 3);
+        out[0] = (g << 5) | b;
+    }
+}
+
 void
 ImagingPackRGB(UINT8 *out, const UINT8 *in, int pixels) {
     int i = 0;
@@ -284,6 +308,30 @@ ImagingPackXRGB(UINT8 *out, const UINT8 *in, int pixels) {
     }
 }
 
+static void
+ImagingPackXBGR1555(UINT8 *out, const UINT8 *in, int pixels) {
+    for (int i = 0; i < pixels; out += 2, in += 4, i++) {
+        /* XBGR, 1/5/5/5 bits per pixel, little-endian */
+        const UINT8 r = in[0] >> 3;
+        const UINT8 g = in[1] >> 3;
+        const UINT8 b = in[2] >> 3;
+        out[1] = 0x80 | (b << 2) | (g >> 3);
+        out[0] = (g << 5) | r;
+    }
+}
+
+static void
+ImagingPackBGR565(UINT8 *out, const UINT8 *in, int pixels) {
+    for (int i = 0; i < pixels; out += 2, in += 4, i++) {
+        /* BGR, 5/6/5 bits per pixel, little-endian */
+        const UINT8 r = in[0] >> 3;
+        const UINT8 g = in[1] >> 2;
+        const UINT8 b = in[2] >> 3;
+        out[1] = (b << 3) | (g >> 3);
+        out[0] = (g << 5) | r;
+    }
+}
+
 void
 ImagingPackBGR(UINT8 *out, const UINT8 *in, int pixels) {
     int i;
@@ -561,10 +609,14 @@ static struct {
     {"PA", "PA;L", 16, packLAL},
 
     /* true colour */
+    {"RGB", "XRGB;1555", 16, ImagingPackXRGB1555},
+    {"RGB", "RGB;565", 16, ImagingPackRGB565},
     {"RGB", "RGB", 24, ImagingPackRGB},
     {"RGB", "RGBX", 32, copy4},
     {"RGB", "RGBA", 32, copy4},
     {"RGB", "XRGB", 32, ImagingPackXRGB},
+    {"RGB", "XBGR;1555", 16, ImagingPackXBGR1555},
+    {"RGB", "BGR;565", 16, ImagingPackBGR565},
     {"RGB", "BGR", 24, ImagingPackBGR},
     {"RGB", "BGRX", 32, ImagingPackBGRX},
     {"RGB", "XBGR", 32, ImagingPackXBGR},
diff --git a/src/libImaging/Unpack.c b/src/libImaging/Unpack.c
index c23d5d889..fbd01b62f 100644
--- a/src/libImaging/Unpack.c
+++ b/src/libImaging/Unpack.c
@@ -764,10 +764,129 @@ ImagingUnpackBGR16(UINT8 *out, const UINT8 *in, int pixels) {
     }
 }
 
+static void
+ImagingUnpackXRGB1555(UINT8 *out, const UINT8 *in, const int pixels) {
+    /* XRGB, 1/5/5/5 bits per pixel, little-endian */
+    for (int i = 0; i < pixels; i++) {
+        const UINT16 pixel = ((UINT16)in[1] << 8) | in[0];
+        const UINT8 r = (pixel >> 10) & 31;
+        const UINT8 g = (pixel >> 5) & 31;
+        const UINT8 b = pixel & 31;
+        out[R] = (r << 3) | (r >> 2);
+        out[G] = (g << 3) | (g >> 2);
+        out[B] = (b << 3) | (b >> 2);
+        out[A] = 255;
+        out += 4;
+        in += 2;
+    }
+}
+
+static void
+ImagingUnpackARGB1555(UINT8 *out, const UINT8 *in, const int pixels) {
+    /* ARGB, 1/5/5/5 bits per pixel, little-endian */
+    for (int i = 0; i < pixels; i++) {
+        const UINT16 pixel = ((UINT16)in[1] << 8) | in[0];
+        const UINT8 r = (pixel >> 10) & 31;
+        const UINT8 g = (pixel >> 5) & 31;
+        const UINT8 b = pixel & 31;
+        out[R] = (r << 3) | (r >> 2);
+        out[G] = (g << 3) | (g >> 2);
+        out[B] = (b << 3) | (b >> 2);
+        out[A] = (pixel >> 15) * 255;
+        out += 4;
+        in += 2;
+    }
+}
+
+static void
+ImagingUnpackARGB1555Z(UINT8 *out, const UINT8 *in, const int pixels) {
+    /* ARGB, 1/5/5/5 bits per pixel, little-endian, inverted alpha */
+    for (int i = 0; i < pixels; i++) {
+        const UINT16 pixel = ((UINT16)in[1] << 8) | in[0];
+        const UINT8 r = (pixel >> 10) & 31;
+        const UINT8 g = (pixel >> 5) & 31;
+        const UINT8 b = pixel & 31;
+        out[R] = (r << 3) | (r >> 2);
+        out[G] = (g << 3) | (g >> 2);
+        out[B] = (b << 3) | (b >> 2);
+        out[A] = ~((pixel >> 15) * 255);
+        out += 4;
+        in += 2;
+    }
+}
+
+static void
+ImagingUnpackXBGR1555(UINT8 *out, const UINT8 *in, const int pixels) {
+    /* XBGR, 1/5/5/5 bits per pixel, little-endian */
+    for (int i = 0; i < pixels; i++) {
+        const UINT16 pixel = ((UINT16)in[1] << 8) | in[0];
+        const UINT8 b = (pixel >> 10) & 31;
+        const UINT8 g = (pixel >> 5) & 31;
+        const UINT8 r = pixel & 31;
+        out[R] = (r << 3) | (r >> 2);
+        out[G] = (g << 3) | (g >> 2);
+        out[B] = (b << 3) | (b >> 2);
+        out[A] = 255;
+        out += 4;
+        in += 2;
+    }
+}
+
+static void
+ImagingUnpackABGR1555(UINT8 *out, const UINT8 *in, const int pixels) {
+    /* ABGR, 1/5/5/5 bits per pixel, little-endian */
+    for (int i = 0; i < pixels; i++) {
+        const UINT16 pixel = ((UINT16)in[1] << 8) | in[0];
+        const UINT8 b = (pixel >> 10) & 31;
+        const UINT8 g = (pixel >> 5) & 31;
+        const UINT8 r = pixel & 31;
+        out[R] = (r << 3) | (r >> 2);
+        out[G] = (g << 3) | (g >> 2);
+        out[B] = (b << 3) | (b >> 2);
+        out[A] = (pixel >> 15) * 255;
+        out += 4;
+        in += 2;
+    }
+}
+
+static void
+ImagingUnpackRGB565(UINT8 *out, const UINT8 *in, const int pixels) {
+    /* RGB, 5/6/5 bits per pixel, little-endian */
+    for (int i = 0; i < pixels; i++) {
+        const UINT16 pixel = ((UINT16)in[1] << 8) | in[0];
+        const UINT8 r = (pixel >> 11) & 31;
+        const UINT8 g = (pixel >> 5) & 63;
+        const UINT8 b = pixel & 31;
+        out[R] = (r << 3) | (r >> 2);
+        out[G] = (g << 2) | (g >> 4);
+        out[B] = (b << 3) | (b >> 2);
+        out[A] = 255;
+        out += 4;
+        in += 2;
+    }
+}
+
+static void
+ImagingUnpackBGR565(UINT8 *out, const UINT8 *in, const int pixels) {
+    /* BGR, 5/6/5 bits per pixel, little-endian */
+    for (int i = 0; i < pixels; i++) {
+        const UINT16 pixel = ((UINT16)in[1] << 8) | in[0];
+        const UINT8 b = (pixel >> 11) & 31;
+        const UINT8 g = (pixel >> 5) & 63;
+        const UINT8 r = pixel & 31;
+        out[R] = (r << 3) | (r >> 2);
+        out[G] = (g << 2) | (g >> 4);
+        out[B] = (b << 3) | (b >> 2);
+        out[A] = 255;
+        out += 4;
+        in += 2;
+    }
+}
+
 void
 ImagingUnpackRGB4B(UINT8 *out, const UINT8 *in, int pixels) {
     int i, pixel;
-    /* RGB, 4 bits per pixel */
+    /* RGB, 4 bits per pixel, little-endian */
     for (i = 0; i < pixels; i++) {
         pixel = in[0] + (in[1] << 8);
         out[R] = (pixel & 15) * 17;
@@ -782,7 +901,7 @@ ImagingUnpackRGB4B(UINT8 *out, const UINT8 *in, int pixels) {
 void
 ImagingUnpackRGBA4B(UINT8 *out, const UINT8 *in, int pixels) {
     int i, pixel;
-    /* RGBA, 4 bits per pixel */
+    /* RGBA, 4 bits per pixel, little-endian */
     for (i = 0; i < pixels; i++) {
         pixel = in[0] + (in[1] << 8);
         out[R] = (pixel & 15) * 17;
@@ -794,6 +913,39 @@ ImagingUnpackRGBA4B(UINT8 *out, const UINT8 *in, int pixels) {
     }
 }
 
+static void
+ImagingUnpackXBGR4(UINT8 *out, const UINT8 *in, const int pixels) {
+    /* XBGR, 4 bits per pixel, little-endian */
+    for (int i = 0; i < pixels; i++) {
+        const UINT8 b = in[1] & 0x0F;
+        const UINT8 g = in[0] & 0xF0;
+        const UINT8 r = in[0] & 0x0F;
+        out[R] = (r << 4) | r;
+        out[G] = g | (g >> 4);
+        out[B] = (b << 4) | b;
+        out[A] = 255;
+        out += 4;
+        in += 2;
+    }
+}
+
+static void
+ImagingUnpackABGR4(UINT8 *out, const UINT8 *in, const int pixels) {
+    /* ABGR, 4 bits per pixel, little-endian */
+    for (int i = 0; i < pixels; i++) {
+        const UINT8 a = in[1] & 0xF0;
+        const UINT8 b = in[1] & 0x0F;
+        const UINT8 g = in[0] & 0xF0;
+        const UINT8 r = in[0] & 0x0F;
+        out[R] = (r << 4) | r;
+        out[G] = g | (g >> 4);
+        out[B] = (b << 4) | b;
+        out[A] = a | (a >> 4);
+        out += 4;
+        in += 2;
+    }
+}
+
 static void
 ImagingUnpackBGRX(UINT8 *_out, const UINT8 *in, int pixels) {
     int i;
@@ -1620,13 +1772,22 @@ static struct {
     {"RGB", "RGB;16B", 48, unpackRGB16B},
     {"RGB", "BGR", 24, ImagingUnpackBGR},
     {"RGB", "RGB;15", 16, ImagingUnpackRGB15},
+    {"RGB", "XRGB;1555", 16, ImagingUnpackXRGB1555},
+    {"RGB", "ARGB;1555", 16, ImagingUnpackARGB1555},
+    {"RGB", "ARGB;1555Z", 16, ImagingUnpackARGB1555Z},
     {"RGB", "BGR;15", 16, ImagingUnpackBGR15},
+    {"RGB", "XBGR;1555", 16, ImagingUnpackXBGR1555},
+    {"RGB", "ABGR;1555", 16, ImagingUnpackABGR1555},
     {"RGB", "RGB;16", 16, ImagingUnpackRGB16},
+    {"RGB", "RGB;565", 16, ImagingUnpackRGB565},
     {"RGB", "BGR;16", 16, ImagingUnpackBGR16},
+    {"RGB", "BGR;565", 16, ImagingUnpackBGR565},
+    {"RGB", "RGB;4B", 16, ImagingUnpackRGB4B},
+    {"RGB", "XBGR;4", 16, ImagingUnpackXBGR4},
+    {"RGB", "ABGR;4", 16, ImagingUnpackABGR4},
+    {"RGB", "BGR;5", 16, ImagingUnpackBGR15}, /* compat */
     {"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},
@@ -1656,6 +1817,9 @@ static struct {
     /* true colour w. alpha */
     {"RGBA", "LA", 16, unpackRGBALA},
     {"RGBA", "LA;16B", 32, unpackRGBALA16B},
+    {"RGBA", "ARGB;1555", 16, ImagingUnpackARGB1555},
+    {"RGBA", "ARGB;1555Z", 16, ImagingUnpackARGB1555Z},
+    {"RGBA", "ABGR;1555", 16, ImagingUnpackABGR1555},
     {"RGBA", "RGBA", 32, copy4},
     {"RGBA", "RGBAX", 40, copy4skip1},
     {"RGBA", "RGBAXX", 48, copy4skip2},
@@ -1671,6 +1835,7 @@ static struct {
     {"RGBA", "BGRA;15", 16, ImagingUnpackBGRA15},
     {"RGBA", "BGRA;15Z", 16, ImagingUnpackBGRA15Z},
     {"RGBA", "RGBA;4B", 16, ImagingUnpackRGBA4B},
+    {"RGBA", "ABGR;4", 16, ImagingUnpackABGR4},
     {"RGBA", "RGBA;16L", 64, unpackRGBA16L},
     {"RGBA", "RGBA;16B", 64, unpackRGBA16B},
     {"RGBA", "BGRA", 32, unpackBGRA},
@@ -1733,8 +1898,13 @@ static struct {
     {"RGBX", "RGB;16B", 48, unpackRGB16B},
     {"RGBX", "BGR", 24, ImagingUnpackBGR},
     {"RGBX", "RGB;15", 16, ImagingUnpackRGB15},
+    {"RGBX", "XRGB;1555", 16, ImagingUnpackXRGB1555},
+    {"RGBX", "RGB;565", 16, ImagingUnpackRGB565},
     {"RGBX", "BGR;15", 16, ImagingUnpackBGR15},
+    {"RGBX", "XBGR;1555", 16, ImagingUnpackXBGR1555},
+    {"RGBX", "BGR;565", 16, ImagingUnpackBGR565},
     {"RGBX", "RGB;4B", 16, ImagingUnpackRGB4B},
+    {"RGBX", "XBGR;4", 16, ImagingUnpackXBGR4},
     {"RGBX", "BGR;5", 16, ImagingUnpackBGR15}, /* compat */
     {"RGBX", "RGBX", 32, copy4},
     {"RGBX", "RGBXX", 40, copy4skip1},