ImageResizer

ImageResizer.cs

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;

namespace Boo
{
    public class ImageResizer
    {
        /// <summary>
        /// Opens an image file, resizes it and returns the resized copy
        /// as a stream.
        /// </summary>
        /// <param name="fileName">Name of the file.</param>
        /// <param name="newWidth">Width of the image to create.</param>
        /// <returns>Stream of the resized image file.</returns>
        public static byte[] GetResizedImage(string fileName, int newWidth)
        {
            var file = new FileInfo(fileName);
            using (Image image = Image.FromFile(file.FullName))
            {
                using (var stream = new MemoryStream())
                {
                    int newHeight = image.Height * newWidth / image.Width;
                    if (image.Width > newWidth && GraphicsSupportsPixelFormat(image.PixelFormat))
                    {
                        using (Image thumbnail = new Bitmap(newWidth, newHeight, image.PixelFormat))
                        {
                            Graphics thumbGraph = Graphics.FromImage(thumbnail);
                            thumbGraph.CompositingQuality = CompositingQuality.HighQuality;
                            thumbGraph.SmoothingMode = SmoothingMode.HighQuality;
                            thumbGraph.InterpolationMode = InterpolationMode.HighQualityBicubic;

                            var rect = new Rectangle(0, 0, newWidth, newHeight);
                            thumbGraph.DrawImage(image, rect);

                            thumbnail.Save(stream, ImageFormat.Jpeg);
                        }
                    }
                    else
                    {
                        image.Save(stream, ImageFormat.Jpeg);
                    }

                    byte[] content = stream.ToArray();
                    return content;
                }
            }
        }

        private static bool GraphicsSupportsPixelFormat(PixelFormat format)
        {
            //  these pixel formats are not supported by the Graphics.FromImage() method
            //  http://msdn.microsoft.com/en-us/library/system.drawing.graphics.fromimage.aspx
            if (format == PixelFormat.Format1bppIndexed ||
                format == PixelFormat.Format4bppIndexed ||
                format == PixelFormat.Format8bppIndexed ||
                format == PixelFormat.Undefined ||
                format == PixelFormat.DontCare ||
                format == PixelFormat.Format16bppArgb1555 ||
                format == PixelFormat.Format16bppGrayScale)
            {
                return false;
            }

            return true;
        }
    }
}