>>726
>>718のように自分で作った場合は責任を持って破棄するか
>>703のようにusingで囲えばg.Dispose()はなくてもいいけど

>>703の訂正版
        private void Form1_Shown(object sender, EventArgs e)
        {
            Bitmap bmp = new Bitmap(400, 400, PixelFormat.Format32bppArgb);
            using (Graphics g = Graphics.FromImage(bmp))
            {
                g.FillEllipse(Brushes.Red, 50, 50, 100, 100);
                //g.Dispose();
            }
            pictureBox1.Image = bmp;
        }