Someone

                if (screenshotFile != "")
                {
                    Surface backbuffer = device.GetBackBuffer(0, 0, BackBufferType.Mono);



                    string extension = CommonFunctions.GetExtension(screenshotFile);

                    if (extension == "jpg")
                        SurfaceLoader.Save(screenshotFile, ImageFileFormat.Jpg, backbuffer);
                    else if (extension == "tga")
                        SurfaceLoader.Save(screenshotFile, ImageFileFormat.Tga, backbuffer);
                    else if (extension == "bmp")
                        SurfaceLoader.Save(screenshotFile, ImageFileFormat.Bmp, backbuffer);
                    else if (extension == "png")
                        SurfaceLoader.Save(screenshotFile, ImageFileFormat.Png, backbuffer);
                    else if (extension == "dds")
                        SurfaceLoader.Save(screenshotFile, ImageFileFormat.Dds, backbuffer);

                    backbuffer.Dispose();


                }