Redimensionar imagem mantendo a proporção (Atualizado).cs

public static System.Drawing.Image Redimensionar(System.Drawing.Image image, int NewWidthMax, int NewHeightMax)
{
	float Fator = 0;
	if (image.Width / WidthMaximo > image.Height / HeightMaximo)
		Fator = (float)image.Width / WidthMaximo;
	else
		Fator = (float)image.Height / HeightMaximo;

	int NewWidth = (int)((float)image.Width / Fator);
	int NewHeight = (int)((float)image.Height / Fator);

	Bitmap newImage = new Bitmap(NewWidth, NewHeight);
	using (Graphics gr = Graphics.FromImage(newImage))
	{
		gr.SmoothingMode = SmoothingMode.HighQuality;
		gr.InterpolationMode = InterpolationMode.HighQualityBicubic;
		gr.PixelOffsetMode = PixelOffsetMode.HighQuality;
		gr.DrawImage(image, new Rectangle(0, 0, NewWidth, NewHeight));
	}
	
	return newImage;
}