fix editing tiled images

Azaion.Common/Extensions/BitmapExtensions.cs

@@ -26,4 +26,14 @@ public static class BitmapExtensions
 
     public static Color CreateTransparent(this Color color, byte transparency) =>
         Color.FromArgb(transparency, color.R, color.G, color.B);
+
+    public static async Task SaveImage(this BitmapSource bitmap, string path, CancellationToken ct = default)
+    {
+        await using var stream = new FileStream(path, FileMode.Create);
+        var encoder = new JpegBitmapEncoder();
+
+        encoder.Frames.Add(BitmapFrame.Create(bitmap));
+        encoder.Save(stream);
+        await stream.FlushAsync(ct);
+    }
 }