diff --git a/src/Makefile b/src/Makefile
index 8d8a25a6..dd2d6177 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -819,7 +819,7 @@ endif
 
 TESTSOBJS = $(patsubst %.c,%.o,$(wildcard tests/*.c)) \
             miscfileformats.o fileformats.o oldies.o libraw2crtc.o \
-			loadsavefuncs.o \
+			loadsavefuncs.o packbits.o \
 			unicode.o \
             io.o realpath.o version.o pversion.o \
 			gfx2surface.o \
diff --git a/src/packbits.c b/src/packbits.c
new file mode 100644
index 00000000..9d7f8c40
--- /dev/null
+++ b/src/packbits.c
@@ -0,0 +1,69 @@
+/* vim:expandtab:ts=2 sw=2:
+*/
+/*  Grafx2 - The Ultimate 256-color bitmap paint program
+
+    Copyright 2018-2019 Thomas Bernard
+    Copyright 2008 Yves Rizoud
+    Copyright 2007 Adrien Destugues
+    Copyright 1996-2001 Sunset Design (Guillaume Dorme & Karl Maritaud)
+
+    Grafx2 is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License
+    as published by the Free Software Foundation; version 2
+    of the License.
+
+    Grafx2 is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Grafx2; if not, see <http://www.gnu.org/licenses/>
+*/
+
+///@file packbits.c
+/// Packbits compression as used in IFF etc.
+/// see http://fileformats.archiveteam.org/wiki/PackBits
+
+#include <stdio.h>
+#include <string.h>
+#include "struct.h"
+#include "gfx2log.h"
+#include "packbits.h"
+
+int PackBits_unpack_from_file(FILE * f, byte * dest, unsigned int count)
+{
+  unsigned int i = 0;
+  while (i < count)
+  {
+    byte cmd;
+    if (fread(&cmd, 1, 1, f) != 1)
+      return PACKBITS_UNPACK_READ_ERROR;
+    if (cmd > 128)
+    {
+      // cmd > 128 => repeat (257 - cmd) the next byte
+      byte v;
+      if (fread(&v, 1, 1, f) != 1)
+        return PACKBITS_UNPACK_READ_ERROR;
+      if (count < (i + 257 - cmd))
+        return PACKBITS_UNPACK_OVERFLOW_ERROR;
+      memset(dest + i, v, (257 - cmd));
+      i += (257 - cmd);
+    }
+    else if (cmd < 128)
+    {
+      // cmd < 128 => copy (cmd + 1) bytes
+      if (count < (i + cmd + 1))
+        return PACKBITS_UNPACK_OVERFLOW_ERROR;
+      if (fread(dest + i, 1, (cmd + 1), f) != (unsigned)(cmd + 1))
+        return PACKBITS_UNPACK_READ_ERROR;
+      i += (cmd + 1);
+    }
+    else
+    {
+      // 128 = NOP
+      GFX2_Log(GFX2_WARNING, "NOP in packbits stream\n");
+    }
+  }
+  return PACKBITS_UNPACK_OK;
+}
diff --git a/src/packbits.h b/src/packbits.h
new file mode 100644
index 00000000..8feb8093
--- /dev/null
+++ b/src/packbits.h
@@ -0,0 +1,41 @@
+/* vim:expandtab:ts=2 sw=2:
+*/
+/*  Grafx2 - The Ultimate 256-color bitmap paint program
+
+    Copyright 2018-2019 Thomas Bernard
+    Copyright 2008 Yves Rizoud
+    Copyright 2007 Adrien Destugues
+    Copyright 1996-2001 Sunset Design (Guillaume Dorme & Karl Maritaud)
+
+    Grafx2 is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License
+    as published by the Free Software Foundation; version 2
+    of the License.
+
+    Grafx2 is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Grafx2; if not, see <http://www.gnu.org/licenses/>
+*/
+
+///@file packbits.h
+/// Packbits compression as used in IFF etc.
+
+#ifndef PACKBITS_H_INCLUDED
+#define PACKBITS_H_INCLUDED
+
+// error codes :
+
+#define PACKBITS_UNPACK_OK 0
+#define PACKBITS_UNPACK_READ_ERROR -1
+#define PACKBITS_UNPACK_OVERFLOW_ERROR -2
+
+/**
+ * @return PACKBITS_UNPACK_OK or PACKBITS_UNPACK_READ_ERROR or PACKBITS_UNPACK_OVERFLOW_ERROR
+ */
+int PackBits_unpack_from_file(FILE * f, byte * dest, unsigned int count);
+
+#endif
diff --git a/src/tests/tests.c b/src/tests/tests.c
index d2b4dc01..fd696fdf 100644
--- a/src/tests/tests.c
+++ b/src/tests/tests.c
@@ -33,6 +33,7 @@
 #include <unistd.h>
 #include "../struct.h"
 #include "../oldies.h"
+#include "../packbits.h"
 #include "../gfx2log.h"
 
 unsigned int MOTO_MAP_pack(byte * packed, const byte * unpacked, unsigned int unpacked_len);
@@ -160,6 +161,7 @@ int Test_Packbits(void)
     NULL
   };
   const long best_packed = 7 + 22 + 23;
+  byte buffer[1024];
 
   snprintf(tempfilename, sizeof(tempfilename), "/tmp/gfx2test-packbits-%lx", random());
   GFX2_Log(GFX2_DEBUG, "tempfile %s\n", tempfilename);
@@ -190,13 +192,30 @@ int Test_Packbits(void)
     return 0;
   }
 
-  // TODO : test unpacking
+  // test unpacking
   f = fopen(tempfilename, "rb");
   if (f == NULL)
   {
     GFX2_Log(GFX2_ERROR, "Failed to open %s for reading\n", tempfilename);
     return 0;
   }
+  for (i = 0; tests[i]; i++)
+  {
+    size_t len = strlen(tests[i]);
+    memset(buffer, 0x80, len);
+    if (PackBits_unpack_from_file(f, buffer, len) != PACKBITS_UNPACK_OK)
+    {
+      GFX2_Log(GFX2_ERROR, "PackBits_unpack_from_file() failed\n");
+      return 0;
+    }
+    if (memcmp(buffer, tests[i], len) != 0)
+    {
+      GFX2_Log(GFX2_ERROR, "uncompressed stream mismatch !\n");
+      GFX2_LogHexDump(GFX2_ERROR, "original ", (const byte *)tests[i], 0, len);
+      GFX2_LogHexDump(GFX2_ERROR, "unpacked ", buffer, 0, len);
+      return 0;
+    }
+  }
   fclose(f);
   unlink(tempfilename);
   return 1; // test OK