Reduce Image Size in C#
Sometimes we have a requirement to reduce the image size programmatically. We can do it in C# by using System.Drawing namespace. In this article we discuss about how can we reduce the image size in C#.
Open Microsoft Visual Studio 2013 => Create new
Console Application. Add new class ImgResizer as shown below.
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
namespace ReduceImage
{
public class ImgResizer
{
private int iFileSizeInBytes;
private string sSourcePath = string.Empty;
private string sOutputPath = string.Empty;
public ImgResizer(int sSize, string sSourcePath, string sOutputPath)
{
iFileSizeInBytes = sSize;
this.sSourcePath = sSourcePath;
this.sOutputPath = sOutputPath;
}
public void ScaleImg()
{
using (MemoryStream ms = new MemoryStream())
{
using (FileStream fs = new FileStream(sSourcePath, FileMode.Open))
{
Bitmap bmp = (Bitmap)Image.FromStream(fs);
SaveTemporary(bmp, ms, 100);
while (ms.Length < 0.9 * iFileSizeInBytes || ms.Length > iFileSizeInBytes)
{
double scale = Math.Sqrt((double)iFileSizeInBytes / (double)ms.Length);
ms.SetLength(0);
bmp = ScaleImg(bmp, scale);
SaveTemporary(bmp, ms, 100);
}
if (bmp != null)
bmp.Dispose();
SaveImgToFile(ms);
}
}
}
private void SaveImgToFile(MemoryStream ms)
{
byte[] data = ms.ToArray();
using (FileStream fs = new FileStream(sOutputPath, FileMode.Create))
{
fs.Write(data, 0, data.Length);
}
}
private void SaveTemporary(Bitmap bmp, MemoryStream ms, int quality)
{
EncoderParameter qualityParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
var codec = GetImgCodecInfo();
var encoderParams = new EncoderParameters(1);
encoderParams.Param[0] = qualityParam;
if (codec != null)
bmp.Save(ms, codec, encoderParams);
else
bmp.Save(ms, GetImgFormat());
}
public Bitmap ScaleImg(Bitmap image, double scale)
{
int newWidth = (int)(image.Width * scale);
int newHeight = (int)(image.Height * scale);
Bitmap result = new Bitmap(newWidth, newHeight, PixelFormat.Format24bppRgb);
result.SetResolution(image.HorizontalResolution, image.VerticalResolution);
using (Graphics g = Graphics.FromImage(result))
{
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.CompositingQuality = CompositingQuality.HighQuality;
g.SmoothingMode = SmoothingMode.HighQuality;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
g.DrawImage(image, 0, 0, result.Width, result.Height);
}
return result;
}
private ImageCodecInfo GetImgCodecInfo()
{
FileInfo fi = new FileInfo(sSourcePath);
switch (fi.Extension)
{
case ".bmp": return ImageCodecInfo.GetImageEncoders()[0];
case ".jpg":
case ".jpeg": return ImageCodecInfo.GetImageEncoders()[1];
case ".gif": return ImageCodecInfo.GetImageEncoders()[2];
case ".tiff": return ImageCodecInfo.GetImageEncoders()[3];
case ".png": return ImageCodecInfo.GetImageEncoders()[4];
default: return null;
}
}
private ImageFormat GetImgFormat()
{
FileInfo fi = new FileInfo(sSourcePath);
switch (fi.Extension)
{
case ".jpg": return ImageFormat.Jpeg;
case ".bmp": return ImageFormat.Bmp;
case ".gif": return ImageFormat.Gif;
case ".png": return ImageFormat.Png;
case ".tiff": return ImageFormat.Tiff;
default: return ImageFormat.Png;
}
}
}
}
Now call ScaleImg() method of ImgResizer class as shown below.
namespace ReduceImage
{
class Program
{
static void Main(string[] args)
{
string sImgPath = @"E:\img.png";
ImgResizer resizer = new ImgResizer(15000, sImgPath, @"E:\img_new.png");
resizer.ScaleImg();
}
}
}
As shown above we are saving reduced image as img_new.png in E drive.
