C# - Square Thumbnail generieren

public Bitmap Generate75x75Pixel(Bitmap image) {
        if(image == null)
            throw new ArgumentNullException("image");

        Bitmap bmp = null;
        Bitmap crapped = null;
        int x = 0, y = 0;
        double prop = 0;

        if(image.Width > 75) {
             // compute proportation
             prop = (double)image.Width / (double)image.Height;

             f(image.Width > image.Height) {
                 x = (int)Math.Round(75 * prop, 0);
                 y = 75;
             }
             else {
                 x = 75;
                 y = (int)Math.Round(75 / prop, 0);
             }

             bmp = new Bitmap((Image)image, new Size(x, y));

             crapped = new Bitmap(75, 75);
             Graphics g = Graphics.FromImage(crapped);
             g.DrawImage(bmp,
                 new Rectangle(0, 0, 75, 75),
                 new Rectangle(0, 0, 75, 75),
                 GraphicsUnit.Pixel);

              bmp = crapped;
        }
        else {
              crapped = image;
        }

        return bmp;
}