datagridviewColumn reference .png or .ico - cellformating.

I was trying change a image of cells in a column, but I only can use the theme reference, how i do to import a image:

Inside the Cellformating method:

if (e.ColumnIndex == 1)
{
if (e.Value.Equals(1))
{
e.CellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter;
e.CellStyle.BackgroundImageSource = “icon-folder”; // this part, i want use other reference.
}
else
{
e.CellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter;
e.CellStyle.BackgroundImageSource = “icon-folder-open”;
}
}