diff --git a/Legacy/PrimeSoft/ImageTHP.cs b/Legacy/PrimeSoft/ImageTHP.cs
new file mode 100644
index 00000000..7438fec3
--- /dev/null
+++ b/Legacy/PrimeSoft/ImageTHP.cs
@@ -0,0 +1,83 @@
+//! \file       ImageTHP.cs
+//! \date       2019 Feb 28
+//! \brief      PrimeSoft image format.
+//
+// Copyright (C) 2019 by morkt
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+
+using System.ComponentModel.Composition;
+using System.IO;
+using System.Windows.Media;
+
+namespace GameRes.Formats.Prime
+{
+    [Export(typeof(ImageFormat))]
+    public class ThpFormat : ImageFormat
+    {
+        public override string         Tag { get { return "THP"; } }
+        public override string Description { get { return "Prime Soft image format"; } }
+        public override uint     Signature { get { return 0; } }
+
+        public override ImageMetaData ReadMetaData (IBinaryStream file)
+        {
+            if (!file.Name.HasExtension ("THP"))
+                return null;
+            var header = file.ReadHeader (4);
+            ushort width  = header.ToUInt16 (0);
+            ushort height = header.ToUInt16 (0);
+            if (width == 0 || width > 0x4000 || height == 0 || height > 0x4000)
+                return null;
+            return new ImageMetaData { Width = width, Height = height, BPP = 8 };
+        }
+
+        public override ImageData Read (IBinaryStream file, ImageMetaData info)
+        {
+            file.Position = 4;
+            var palette = ReadPalette (file.AsStream, 0x100, PaletteFormat.Bgr);
+            int stride = (info.iWidth + 3) & ~3;
+            var pixels = new byte[info.iHeight * stride];
+            int length = info.iHeight * info.iWidth;
+            int dst = 0;
+            while (dst < length)
+            {
+                byte px = file.ReadUInt8();
+                int next = file.PeekByte();
+                if (px == next)
+                {
+                    file.ReadByte();
+                    int count = file.ReadByte() + 1;
+                    while (count --> 0)
+                    {
+                        pixels[dst++] = px;
+                    }
+                }
+                else
+                    pixels[dst++] = px;
+            }
+            return ImageData.CreateFlipped (info, PixelFormats.Indexed8, palette, pixels, stride);
+        }
+
+        public override void Write (Stream file, ImageData image)
+        {
+            throw new System.NotImplementedException ("ThpFormat.Write not implemented");
+        }
+    }
+}