diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index 8b95cd9a..78b9dbb5 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -99,6 +99,7 @@
     <Compile Include="BeF\ImageALO.cs" />
     <Compile Include="BellDa\ArcDAT.cs" />
     <Compile Include="BellDa\AudioPW.cs" />
+    <Compile Include="Bishop\ArcPK.cs" />
     <Compile Include="BlackRainbow\ArcCCF.cs" />
     <Compile Include="BlackRainbow\ArcIMP.cs" />
     <Compile Include="BlackRainbow\ArcSPPAK.cs" />
@@ -111,6 +112,7 @@
     <Compile Include="Cyberworks\ArcApp.cs" />
     <Compile Include="DirectDraw\DxtDecoder.cs" />
     <Compile Include="elf\ArcAi5DAT.cs" />
+    <Compile Include="elf\ImageRMT.cs" />
     <Compile Include="ExHibit\ArcGRP.cs" />
     <Compile Include="Foster\ArcC24.cs" />
     <Compile Include="Foster\ArcFA2.cs" />
diff --git a/ArcFormats/elf/ImageRMT.cs b/ArcFormats/elf/ImageRMT.cs
new file mode 100644
index 00000000..75cb71be
--- /dev/null
+++ b/ArcFormats/elf/ImageRMT.cs
@@ -0,0 +1,81 @@
+//! \file       ImageRMT.cs
+//! \date       2017 Dec 11
+//! \brief      Ai5 engine compressed image format.
+//
+// Copyright (C) 2017 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;
+using GameRes.Compression;
+
+namespace GameRes.Formats.Elf
+{
+    [Export(typeof(ImageFormat))]
+    public class RmtFormat : ImageFormat
+    {
+        public override string         Tag { get { return "RMT"; } }
+        public override string Description { get { return "Ai5 engine compressed image format"; } }
+        public override uint     Signature { get { return 0x20544D52; } } // 'RMT '
+
+        public override ImageMetaData ReadMetaData (IBinaryStream file)
+        {
+            var header = file.ReadHeader (0x14);
+            return new ImageMetaData {
+                OffsetX = header.ToInt32 (4),
+                OffsetY = header.ToInt32 (8),
+                Width   = header.ToUInt32 (0xC),
+                Height  = header.ToUInt32 (0x10),
+                BPP     = 32,
+            };
+        }
+
+        public override ImageData Read (IBinaryStream file, ImageMetaData info)
+        {
+            int stride = (int)info.Width * 4;
+            var pixels = new byte[stride * (int)info.Height];
+            file.Position = 0x14;
+            using (var input = new LzssStream (file.AsStream, LzssMode.Decompress, true))
+                input.Read (pixels, 0, pixels.Length);
+            for (int i = 4; i < stride; i += 4)
+            {
+                pixels[i  ] += pixels[i-4];
+                pixels[i+1] += pixels[i-3];
+                pixels[i+2] += pixels[i-2];
+                pixels[i+3] += pixels[i-1];
+            }
+            for (int i = stride; i < pixels.Length; i += 4)
+            {
+                pixels[i  ] += pixels[i-stride];
+                pixels[i+1] += pixels[i-stride+1];
+                pixels[i+2] += pixels[i-stride+2];
+                pixels[i+3] += pixels[i-stride+3];
+            }
+            return ImageData.CreateFlipped (info, PixelFormats.Bgra32, null, pixels, stride);
+        }
+
+        public override void Write (Stream file, ImageData image)
+        {
+            throw new System.NotImplementedException ("RmtFormat.Write not implemented");
+        }
+    }
+}