WebPFrameSettings Class

public sealed class WebPFrameSettings

using (var writer = new WebPWriter(@"Images\Output\AnimatedWebP.webp"))
{
    writer.FrameOptions.Delay = 250;

    for (int i = 0; i < 400; i += 25)
    {
        var bitmap = new Bitmap(400, 100, PixelFormat.Format24bppRgb, RgbColor.Yellow);

        using (var graphics = bitmap.GetAdvancedGraphics())
        {
            graphics.FillEllipse(new SolidBrush(RgbColor.Green), new System.Drawing.RectangleF(i, 0, 100, 100));
        }

        Pipeline.Run(bitmap + writer);
    }
}