C# Image exaple

 

public void Save(Bitmap image, int quality, string filePath, int startx, int endy)
        {
            // Get the image's original width and height
            int originalWidth = image.Width;
            int originalHeight = image.Height;

            // To preserve the aspect ratio
            float ratioX = (float)startx / (float)originalWidth;
            float ratioY = (float)endy / (float)originalHeight;
            float ratio = Math.Min(ratioX, ratioY);

            // New width and height based on aspect ratio
            int newWidth = (int)(originalWidth * ratio);
            int newHeight = (int)(originalHeight * ratio);

            // Convert other formats (including CMYK) to RGB.
            Bitmap newImage = new Bitmap(newWidth, newHeight, PixelFormat.Format24bppRgb);

            // Draws the image in the specified size with quality mode set to HighQuality
            using (Graphics graphics = Graphics.FromImage(newImage))
            {
                graphics.CompositingQuality = CompositingQuality.HighQuality;
                graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                graphics.SmoothingMode = SmoothingMode.HighQuality;
                graphics.DrawImage(image, 0, 0, newWidth, newHeight);
            }

            // Get an ImageCodecInfo object that represents the JPEG codec.
            ImageCodecInfo imageCodecInfo = this.GetEncoderInfo(ImageFormat.Jpeg);

            // Create an Encoder object for the Quality parameter.
            Encoder encoder = Encoder.Quality;

            // Create an EncoderParameters object. 
            EncoderParameters encoderParameters = new EncoderParameters(1);

            // Save the image as a JPEG file with quality level.
            EncoderParameter encoderParameter = new EncoderParameter(encoder, quality);
            encoderParameters.Param[0] = encoderParameter;
            string filepath = filePath + DateTime.Now.ToString("yyyyMMddHHmmss") + DateTime.Now.Millisecond.ToString();
            newImage.Save(filepath + "psvv.png", imageCodecInfo, encoderParameters);
        }



        /// <summary>
        /// Method to get encoder infor for given image format.
        /// </summary>
        /// <param name="format">Image format</param>
        /// <returns>image codec info.</returns>
        private ImageCodecInfo GetEncoderInfo(ImageFormat format)
        {
            return ImageCodecInfo.GetImageDecoders().SingleOrDefault(c => c.FormatID == format.Guid);
        }