HI. I know this is simple question but when I use

 FirstPersonTestImage.Save(IIdComboBox.Text + "-" + i + ".jpg");

it works and saves file to folder where is the .exe file . But I want to save it to specific folder like /photo/IO-66/ and tryed to use

 String StudentPath = PhotoPath + IGroupNoComboBox.Text + "/" + IIdComboBox.Text + "/" + IIdComboBox.Text + "-" + i + ".jpg";

 FirstPersonTestImage.Save(StudentPath);

BUt it gives

An unhandled exception of type 'System.Runtime.InteropServices.ExternalException' occurred in System.Drawing.dll

How can I solve this problem? Is is about folder path ? or using "/" ?

EDIT

Here My code for creating and checking existing or not folder

  if (!System.IO.Directory.Exists(PhotoPath + "/" + IGroupNoComboBox.Text.ToString().Trim()))
            {

               Directory.CreateDirectory(PhotoPath + "/" + IGroupNoComboBox.Text.ToString().Trim());


            }

             if (!System.IO.Directory.Exists(PhotoPath + "/" + IGroupNoComboBox.Text.ToString().Trim()+ "/" + IIdComboBox.Text.ToString().Trim() + "/"))
            {

                Directory.CreateDirectory(PhotoPath + "/" + IGroupNoComboBox.Text.ToString().Trim()+"/" + IIdComboBox.Text.ToString().Trim() + "/");

            }