.NET Image Manipulation programmatically

Sometimes developer need to do image manipulation pro grammatically:

1. Resizing the image width/height.
2. Change image format.
3. Decrease image quality to decrease image size.
   

Code Below will help developers to do these tasks:

1. We will declare variable for new image width, height, Quality(1-100), extension.
2. Create Bitmap from physical file or stream.
   
   



// Create a bitmap from the stream Bitmap oldImage = new Bitmap(filename);



3. Initialize new bitmap using new width and height.
   
   

// Initialize new bitmap using new width and height. Bitmap newImage = new Bitmap(Width,Height, System.Drawing.Imaging.PixelFormat.Format32bppRgb);

4. Initialize graphic from new image.
5. Draw old image with new width and height to new image variable.

Graphics g = Graphics.FromImage(newImage); g.DrawImage(oldImage,0,0,newImage.Width,newImage.Height);

6. Before we save image we need get encoder of its new type.
   

private ImageCodecInfo GetEncoderInfo(String mimeType) { ImageCodecInfo[] encoders; encoders = ImageCodecInfo.GetImageEncoders(); for(int _iLoop = 0; _iLoop<encoders.Length; ++j) { if(encoders[_iLoop].MimeType == mimeType) { return encoders[_iLoop]; } } return null; }

7. Last step will save image with its new configurations:
   



EncoderParameters imgParams = new EncoderParameters(1); imgParams.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality,Quality); ImageCodecInfo ici = GetEncoderInfo(sMime); ImageCodecInfo newici = GetEncoderInfo(sNewMime); imgBitMap.Save(newstream, newici,imgParams);