diff --git a/ArcFormats/CsWare/ImageB5.cs b/ArcFormats/CsWare/ImageB5.cs
new file mode 100644
index 00000000..7e57eca0
--- /dev/null
+++ b/ArcFormats/CsWare/ImageB5.cs
@@ -0,0 +1,144 @@
+//! \file       ImageB5.cs
+//! \date       2018 Mar 26
+//! \brief      CsWare image format.
+//
+// Copyright (C) 2018 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;
+using System.ComponentModel.Composition;
+using System.IO;
+using System.Windows.Media;
+
+namespace GameRes.Formats.CsWare
+{
+    internal class B5MetaData : ImageMetaData
+    {
+        public bool SwapRgb;
+    }
+
+    [Export(typeof(ImageFormat))]
+    public class B5Format : ImageFormat
+    {
+        public override string         Tag { get { return "B5"; } }
+        public override string Description { get { return "CsWare image format"; } }
+        public override uint     Signature { get { return 0x773562; } } // 'b5w'
+
+        public override ImageMetaData ReadMetaData (IBinaryStream file)
+        {
+            var header = file.ReadHeader (8);
+            return new B5MetaData {
+                Width  = header.ToUInt16 (4),
+                Height = header.ToUInt16 (6),
+                BPP = 16,
+                SwapRgb = header[2] != 'w',
+            };
+        }
+
+        public override ImageData Read (IBinaryStream file, ImageMetaData info)
+        {
+            var reader = new B5Reader (file, (B5MetaData)info);
+            reader.Unpack();
+            return ImageData.Create (info, PixelFormats.Bgr555, null, reader.Data);
+        }
+
+        public override void Write (Stream file, ImageData image)
+        {
+            throw new System.NotImplementedException ("B5Format.Write not implemented");
+        }
+    }
+
+    internal class B5Reader
+    {
+        IBinaryStream   m_input;
+        ushort[]        m_output;
+        int             m_width;
+        int             m_height;
+        bool            m_swap;
+
+        public Array    Data { get { return m_output; } }
+
+        public B5Reader (IBinaryStream input, B5MetaData info)
+        {
+            m_input = input;
+            m_width = (int)info.Width;
+            m_height = (int)info.Height;
+            m_swap = info.SwapRgb;
+            m_output = new ushort[m_width * m_height];
+        }
+
+        public void Unpack ()
+        {
+            InitOffsetsTable();
+            m_input.Position = 8;
+            int dst_row = 0;
+            for (int y = 0; y < m_height; ++y)
+            {
+                int dst = dst_row;
+                for (int w = m_width; w > 0; )
+                {
+                    ushort v = m_input.ReadUInt16();
+                    if (0 != (v & 0x8000))
+                    {
+                        if (m_swap)
+                            v = (ushort)(((v | 0xFFE0) << 10) | (v >> 10) & 0x1F | v & 0x3E0);
+                        else
+                            v = (ushort)(v & 0x7FFF);
+                        m_output[dst++] = v;
+                        w--;
+                    }
+                    else
+                    {
+                        int count = v & 0xFF;
+                        int src = m_offsets[v >> 8];
+                        w -= count;
+                        while (count --> 0)
+                        {
+                            m_output[dst] = m_output[dst+src];
+                            ++dst;
+                        }
+                    }
+                }
+                dst_row += m_width;
+            }
+        }
+
+        int[] m_offsets = new int[128];
+
+        void InitOffsetsTable ()
+        {
+            int i = 0;
+            for (int x = -1; x >= -8; --x)
+            {
+                m_offsets[i++] = x;
+            }
+            int offset = -m_width;
+            for (int y = 8; y > 0; --y)
+            {
+                for (int x = 6; x >= -8; --x)
+                {
+                    m_offsets[i++] = offset + x;
+                }
+                offset -= m_width;
+            }
+        }
+    }
+}