diff --git a/Legacy/Legacy.csproj b/Legacy/Legacy.csproj
index d8be698d..32ed679a 100644
--- a/Legacy/Legacy.csproj
+++ b/Legacy/Legacy.csproj
@@ -216,6 +216,7 @@
     <Compile Include="WestGate\ImageNBMP.cs" />
     <Compile Include="Witch\ArcARC.cs" />
     <Compile Include="Yaneurao\ArcSDA.cs" />
+    <Compile Include="Yaneurao\ImageGTO.cs" />
     <Compile Include="Yaneurao\ImageYGA.cs" />
     <Compile Include="YellowCap\ImageGEF.cs" />
     <Compile Include="YellowCap\ImageGGF.cs" />
diff --git a/Legacy/Yaneurao/ImageGTO.cs b/Legacy/Yaneurao/ImageGTO.cs
new file mode 100644
index 00000000..729851c9
--- /dev/null
+++ b/Legacy/Yaneurao/ImageGTO.cs
@@ -0,0 +1,103 @@
+//! \file       ImageGTO.cs
+//! \date       2018 Dec 20
+//! \brief      Yaneurao obfuscated bitmap.
+//
+// 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.ComponentModel.Composition;
+using System.IO;
+using System.Windows.Media;
+
+// [000428][Apple Pie] Seishun Ouka
+
+namespace GameRes.Formats.Yaneurao
+{
+    [Export(typeof(ImageFormat))]
+    public class GtoFormat : ImageFormat
+    {
+        public override string         Tag { get { return "GTO"; } }
+        public override string Description { get { return "Yaneurao obfuscated bitmap"; } }
+        public override uint     Signature { get { return 0; } }
+
+        public override ImageMetaData ReadMetaData (IBinaryStream file)
+        {
+            var header = file.ReadHeader (2);
+            if (!header.AsciiEqual ("NY"))
+                return null;
+            file.Position = 0;
+            using (var input = OpenGtoStream (file))
+                return Bmp.ReadMetaData (input);
+        }
+
+        public override ImageData Read (IBinaryStream file, ImageMetaData info)
+        {
+            using (var input = OpenGtoStream (file))
+                return Bmp.Read (input, info);
+        }
+
+        internal IBinaryStream OpenGtoStream (IBinaryStream file)
+        {
+            var input = new SubFilterStream (file.AsStream, 0xC, true);
+            return new BinaryStream (input, file.Name);
+        }
+
+        public override void Write (Stream file, ImageData image)
+        {
+            throw new System.NotImplementedException ("GtoFormat.Write not implemented");
+        }
+    }
+
+    public class SubFilterStream : ProxyStream
+    {
+        private byte        m_key;
+
+        public override bool CanWrite { get { return false; } }
+
+        public SubFilterStream (Stream stream, byte key, bool leave_open = false)
+            : base (stream, leave_open)
+        {
+            m_key = key;
+        }
+
+        #region System.IO.Stream methods
+        public override int Read (byte[] buffer, int offset, int count)
+        {
+            int read = BaseStream.Read (buffer, offset, count);
+            for (int i = 0; i < read; ++i)
+            {
+                buffer[offset+i] -= m_key;
+            }
+            return read;
+        }
+
+        public override int ReadByte ()
+        {
+            int b = BaseStream.ReadByte();
+            if (-1 != b)
+            {
+                b = (b - m_key) & 0xFF;
+            }
+            return b;
+        }
+        #endregion
+    }
+}