C#: Resize Image

// Default parameters are almost the highest quality setting.
public static Bitmap Resize(this Image src, int w, int h, 
    SmoothingMode smoothingMode = SmoothingMode.AntiAlias,
    InterpolationMode interpolationMode = InterpolationMode.HighQualityBicubic,
    PixelOffsetMode pixelOffsetMode = PixelOffsetMode.HighQuality)
{
    var newImage = new Bitmap(w, h);
    using (var gr = Graphics.FromImage(newImage))
    {
        gr.SmoothingMode = smoothingMode;
        gr.InterpolationMode = interpolationMode;
        gr.PixelOffsetMode = pixelOffsetMode;
        gr.DrawImage(src, 0, 0, w, h);
    }
    return newImage;
}

// resize image based on given percentage
public static Bitmap ResizedByPercentage(this Image src, double percent)
{
    var rW = (int)Math.Round(src.Width * percent, 0);
    var rH = (int)Math.Round(src.Height * percent, 0);
    return src.Resize(rW, rH);
}

// resize image limited in given w, h parameter
public static Bitmap ResizeImageIn(this Image src, int w, int h)
{
    var rW = (double)w / src.Width;
    var rH = (double)h / src.Height;
    var rWIsSmall = rW < rH;
    return src.Resize(rWIsSmall ? w : (int)(src.Width * rH), rWIsSmall ? (int)(src.Height * rW) : h);
}