diff --git a/FFMpegCore/Extend/BitmapExtensions.cs b/FFMpegCore/Extend/BitmapExtensions.cs
index bf10336..e2f5505 100644
--- a/FFMpegCore/Extend/BitmapExtensions.cs
+++ b/FFMpegCore/Extend/BitmapExtensions.cs
@@ -6,7 +6,7 @@ namespace FFMpegCore.Extend
 {
     public static class BitmapExtensions
     {
-        public static bool AddAudio(this Bitmap poster, string audio, string output)
+        public static bool AddAudio(this Image poster, string audio, string output)
         {
             var destination = $"{Environment.TickCount}.png";
             poster.Save(destination);