Resize Image in asp.net in C#

This is a code in C# to resize an image. it takes two inputs as target image size and the image in byte format and it'll will return target sized image.

Some terms used in the code:-
Format24bppRgb - It specifies that formate is 24 bit per pixel and for each colour that is red, green and blue 8 bits are used



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

public class ImageClass
{

private static byte[] ResizeImageFile(byte[] imageFile, int targetSize)
{
using (System.Drawing.Image oldImage = System.Drawing.Image.FromStream(new MemoryStream(imageFile)))
{
Size newSize = CalculateDimensions(oldImage.Size, targetSize);//User defined function to calculate image dimensions
using (Bitmap newImage = new Bitmap(newSize.Width, newSize.Height, PixelFormat.Format24bppRgb))
{
using (Graphics canvas = Graphics.FromImage(newImage))
{
canvas.SmoothingMode = SmoothingMode.AntiAlias;//set rendering quality of canvas
canvas.InterpolationMode = InterpolationMode.HighQualityBicubic;//set interpolation mode to HighQualityBiubic
canvas.PixelOffsetMode = PixelOffsetMode.HighQuality;
canvas.DrawImage(oldImage, new Rectangle(new Point(0, 0), newSize));//drow image in canvas with new size and with specific starting location
MemoryStream m = new MemoryStream();
newImage.Save(m, ImageFormat.Jpeg);//define image formate in which it is to be shown
return m.GetBuffer();//return image as byte array
}
}
}
}

private static Size CalculateDimensions(Size oldSize, int targetSize)
{
Size newSize = new Size();

//change the size according to the widh and height
if (oldSize.Height > oldSize.Width)
{
newSize.Width = (int)(oldSize.Width * ((float)targetSize / (float)oldSize.Height));
newSize.Height = targetSize;
}
else
{
newSize.Width = targetSize;
newSize.Height = (int)(oldSize.Height * ((float)targetSize / (float)oldSize.Width));
}
return newSize;
}
}