DataGridViewCell holding on to image -- cannot delete

I have a simple datagridview with 3 columns, one of which is an image column.  I added a context menu to the image column to allow for selecting and removing images.

When an image is selected, it is copied to a local folder.  When an image is removed, the following code is executed:

private void btnRemoveImage_Click(object sender, EventArgs e) { //dispose image object ((Image)_currentCell.Value).Dispose(); _currentCell.Value = null; //get filename string fileToDelete =  dgSponsors.Rows[_currentCell.RowIndex].Cells["colImageFilename"].Value.ToString(); //delete the file if(File.Exists(fileToDelete))  //the file DOES exist   File.Delete(fileToDelete);  //this does NOT throw an exception //at this point the file is still visible in the directory and I can delete it without problems manually (ie:  nothing is holding on to it anymore) //reset hidden column values dgSponsors.Rows[_currentCell.RowIndex].Cells["colImageSelected"].Value = false; dgSponsors.Rows[_currentCell.RowIndex].Cells["colImageFilename"].Value = ""; }

Can anyone help me troubleshoot this