public class MiaColonna : DataGridViewColumn 
    { 
        public MiaColonna() : base() 
        { 
             
            this.CellTemplate = new MiaCella(); 
        } 

        public override DataGridViewCell CellTemplate 
        { 
            get 
            { 
                return base.CellTemplate; 
            } 
            set 
            { 
                base.CellTemplate = value; 
            } 
        } 


        public class MiaCella : DataGridViewCell 
        { 
            private Button b; 
            public MiaCella(): base() 
            { 
                b = new Button(); 
                this.b.Text = "Bottone di prova"; 
                b.Image = Image.FromFile("C:\prova.jpg"); 
            } 
            protected override void Paint(Graphics graphics, Rectangle clipBounds, Rectangle cellBounds, int rowIndex, DataGridViewElementStates cellState, object value, object formattedValue, string errorText, DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle, DataGridViewPaintParts paintParts) 
            { 
                base.Paint(graphics, clipBounds, cellBounds, rowIndex, cellState, value, formattedValue, errorText, cellStyle, advancedBorderStyle, paintParts); 

                Rectangle dimensioni = new Rectangle(cellBounds.Location.X, cellBounds.Location.Y, cellBounds.Size.Width, cellBounds.Size.Height); 
                b.Size = dimensioni.Size; 
                b.Location = dimensioni.Location; 
                this.DataGridView.Controls.Add(b); 
            } 
        } 
    }