C#

PictureBox CreateCircularPicture(Image image)
{
    PictureBox pictureBox = new PictureBox();
    float smallestDimension = image.Width;
    if (image.Height < smallestDimension)
        smallestDimension = image.Height;
    System.Drawing.Drawing2D.GraphicsPath myGraphicsPath = new System.Drawing.Drawing2D.GraphicsPath();
    myGraphicsPath.AddEllipse(0, 0, smallestDimension, smallestDimension);
    pictureBox.Region = new Region(myGraphicsPath);
    pictureBox.Image = image;
    pictureBox.Height = (int)smallestDimension;
    pictureBox.Width = (int)smallestDimension;
    return pictureBox;
}

List<Foo> AcceptAndReturnListFoo(List<foo> foo){
}

public Image AdjustImage(Image image, float opacity)
{
    Bitmap bitmap = new Bitmap(image.Width, image.Height);
    using (Graphics g = Graphics.FromImage(bitmap))
    {
        ColorMatrix matrix = new ColorMatrix();
        matrix.Matrix33 = opacity;
        ImageAttributes attributes = new ImageAttributes();
        attributes.SetColorMatrix(matrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
        g.DrawImage(
            image, new Rectangle(
                0, 0, bitmap.Width, bitmap.Height),
                0, 0, image.Width, image.Height, GraphicsUnit.Pixel, attributes);
    }
    return bitmap;
}

public static Image SetImageOpacity(Image image, float opacity)
{
     Bitmap bitmap = new Bitmap(image.Width, image.Height); 
     using (Graphics g = Graphics.FromImage(bitmap)) 
     {
          // The followine statement was absent originally.
          g.FillRegion(new SolidBrush(SystemColors.Window), new Region(new Rectangle(0, 0, image.Width, image.Height)));
          ColorMatrix matrix = new ColorMatrix();
          matrix.Matrix33 = opacity; 
          ImageAttributes attributes = new ImageAttributes(); 
          attributes.SetColorMatrix(matrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap); 
          g.DrawImage(image, new Rectangle(0, 0, bitmap.Width, bitmap.Height), 0, 0, image.Width, image.Height, GraphicsUnit.Pixel, attributes); 
     } 
     return bitmap; 
}