@mansur.nurani
I suggest you to please try using following example for your kind reference.
//Creates an instance of Image
using (Aspose.PSD.Image image = new Aspose.PSD.FileFormats.Psd.PsdImage(500, 500))
{
//Creates and initialize an instance of Graphics class
Aspose.PSD.Graphics graphics = new Aspose.PSD.Graphics(image);
//Clears Graphics surface
graphics.Clear(Color.Wheat);
//Creates an instance of Font
Aspose.PSD.Font font = new Aspose.PSD.Font("Times New Roman", 16);
//Create an instance of SolidBrush having Red Color
Aspose.PSD.Brushes.SolidBrush brush = new Aspose.PSD.Brushes.SolidBrush(Color.Red);
//Draw a String
graphics.DrawString("Created by Aspose.PSD for .Net", font, brush, new PointF(100, 100));
// create export options.
Aspose.PSD.ImageOptions.GifOptions options = new Aspose.PSD.ImageOptions.GifOptions();
// save all changes
image.Save("C:\\temp\\output.gif", options);
}