The output image after cropping is larger than the original

Question

When I crop an Image using Bitmap.Clone() it creates output larger than the original image Size
The Original size is : 5 M
and the Output Cropped image is : 28 M

How can I make cropping without losing quality and with no large size? 

My code is :

private static Image cropImage(Image img, Rectangle cropArea)
{
  var bmpImage = new Bitmap(img);
  Bitmap bmpCrop = bmpImage.Clone(cropArea, bmpImage.PixelFormat);
  img.Dispose();
  bmpCrop.Save(@"D:\Work\CropImage\CropImage\crop.bmp",bmpImage.RawFormat );
  return (Image)(bmpCrop);
}