diff --git a/GameRes/ImageDecoder.cs b/GameRes/ImageDecoder.cs
index 7d59f705..f1d6ffa9 100644
--- a/GameRes/ImageDecoder.cs
+++ b/GameRes/ImageDecoder.cs
@@ -80,6 +80,13 @@ namespace GameRes
             Info = format.Item2;
         }
 
+        public ImageFormatDecoder (IBinaryStream file, ImageFormat format, ImageMetaData info)
+        {
+            m_file = file;
+            SourceFormat = format;
+            Info = info;
+        }
+
         bool m_disposed = false;
         public void Dispose ()
         {
@@ -114,6 +121,12 @@ namespace GameRes
             m_input = input;
         }
 
+        protected BinaryImageDecoder (IBinaryStream input, ImageMetaData info)
+        {
+            m_input = input;
+            Info = info;
+        }
+
         protected abstract ImageData GetImageData ();
 
         #region IDisposable members