How to Set size for picture in datadrigview

Image img = Image.FromFile(@"c:\pradipH.jpg");
Image thumb = img.GetThumbnailImage(100, 100, null, IntPtr.Zero);

DataGridViewImageColumn imageColumn;
int columnCount = 0;
do
{
imageColumn = new DataGridViewImageColumn();
imageColumn.Width = 100;
dataGridView1.Columns.Add(imageColumn);

dataGridView1.Rows[0].Cells[columnCount].Value = thumb;
dataGridView1.Rows[0].Height = 100;

columnCount = columnCount + 1;
}
while (columnCount < 3);

Image img=Image.FromFile(@"\\192.168.10.248\xxx" + l4AnalysesDataGridView.Rows[0].Cells[9].Value.ToString().Substring(2));
Image thumb = img.GetThumbnailImage(300, 400, null, IntPtr.Zero);
DataGridViewImageColumn imageColum1=new DataGridViewImageColumn();
imageColum1.Width = 400;
dataGridView1.Columns.Add(imageColum1);

dataGridView1.Rows[0].Cells[4].Value = thumb;
dataGridView1.Rows[0].Height = 300;