diff --git a/pk3DS/3DS/DARC.cs b/pk3DS/3DS/DARC.cs
index 70d0d76..eb0d1f1 100644
--- a/pk3DS/3DS/DARC.cs
+++ b/pk3DS/3DS/DARC.cs
@@ -338,7 +338,8 @@ internal static bool insertFile(ref DARC orig, int index, byte[] data)
                 // Fix Offset references of other files
                 foreach (var x in orig.Entries.Where(x => x.DataOffset >= offset + oldLength))
                     x.DataOffset += (uint) diff;
-                orig.Entries[index].DataLength = (uint)data.Length;
+                orig.Entries[index].DataLength = (uint)data.Length; 
+                orig.Header.FileSize += (uint)diff;
                 return true;
             }
             catch (Exception) { return false; }