ImageList img = new ImageList();
img.Images.Add(Image.FromFile("C:\\Program Files (x86)\\GrapeCity\\Spread Studio\\Common\\CC logo.png"));
img.Images.Add(Image.FromFile("C:\\Program Files (x86)\\GrapeCity\\Spread Studio\\Common\\clkEditor.jpg"));
img.Images.Add(Image.FromFile("C:\\Program Files (x86)\\GrapeCity\\Spread Studio\\Common\\sd.ico"));
GrapeCity.Win.Spread.InputMan.CellType.GcComboBoxCellType gccombo = new GrapeCity.Win.Spread.InputMan.CellType.GcComboBoxCellType();
gccombo.Items.Add("Gouda");
gccombo.Items.Add("Swiss");
gccombo.Items.Add("Brie");
gccombo.Items[0].BackColor = Color.Beige;
gccombo.Items[1].BackColor = Color.Cornsilk;
gccombo.Items[2].BackColor = Color.PeachPuff;
gccombo.ImageList = img;
gccombo.Items[0].Image = 0;
gccombo.Items[1].Image = 1;
gccombo.Items[2].Image = 2;
gccombo.ShowListBoxImage = true;
gccombo.ImageAlign = HorizontalAlignment.Right;
gccombo.ImageWidth = 50;
fpSpread1.Sheets[0].Cells[1, 1].CellType = gccombo;