public void ResizeFromStream(string ImageSavePath, int MaxSideSize, Stream Buffer) 
{ 
int intNewWidth; 
int intNewHeight; 
Image imgInput = Image.FromStream(Buffer); 

//Determine image format 
ImageFormat fmtImageFormat = imgInput.RawFormat; 

//get image original width and height 
int intOldWidth = imgInput.Width; 
int intOldHeight = imgInput.Height; 

//determine if landscape or portrait 
int intMaxSide; 

if (intOldWidth >= intOldHeight) 
{ 
intMaxSide = intOldWidth; 
} 
else 
{ 
intMaxSide = intOldHeight; 
} 


if (intMaxSide > MaxSideSize) 
{ 
//set new width and height	
double dblCoef = MaxSideSize / (double)intMaxSide; 
i ntNewWidth = Convert.ToInt32(dblCoef * intOldWidth); 
intNewHeight = Convert.ToInt32(dblCoef * intOldHeight); 
} 
else 
{ 
intNewWidth = intOldWidth; 
intNewHeight = intOldHeight; 
} 
//create new bitmap 
Bitmap bmpResized = new Bitmap(imgInput, intNewWidth, intNewHeight); 

//save bitmap to disk 
bmpResized.Save(ImageSavePath, fmtImageFormat); 

//release used resources 
imgInput.Dispose(); 
bmpResized.Dispose(); 
Buffer.Close(); 
}

Image Upload and Resize

ASP.NET Image Upload and Resize

aspnet

C#