A generic error occurred in GDI error when save bar code ima

Problem

when i press button preview to show barcode it give me error as following

at System.Drawing.Image.Save(String filename, ImageCodecInfo encoder, EncoderParameters encoderParams)
at System.Drawing.Image.Save(String filename, ImageFormat format)
at System.Drawing.Image.Save(String filename)
at BarcodesPrinting.BtnPreviwe_Click(Object sender, EventArgs e) in D:\Engaz\TABSolutions\MiniTAB\Trunk\Code\Tab\BarCode\Rpts\BarcodesPrinting.cs:line 707
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

the error display on this line

picItem.Image.Save(BarcodePath);

my code

BarcodePath = Application.StartupPath + @"\images\barcode.png";
private void BtnPreviwe_Click(object sender, EventArgs e)
{
CreateBarcode(txtFromItem.Text.Trim());
picItem.Image.Save(BarcodePath);
}

createbarcode function

private void CreateBarcode(string barcodeText = "")
{
string sql = " select * from BarCodeDesign where SizeCode=" + txtBarCodeDesign.Text;
DataTable tbRes = DataAccess.ExecuteDataTable(sql);
if (tbRes.Rows.Count > 0)
{
sizeCode = Convert.ToInt32(txtBarCodeDesign.Text);
int W = Convert.ToInt32(string.IsNullOrEmpty(Convert.ToString(tbRes.Rows[0]["BarcodeWidth"])) ? "100" : Convert.ToString(tbRes.Rows[0]["BarcodeWidth"]));
int H = Convert.ToInt32(string.IsNullOrEmpty(Convert.ToString(tbRes.Rows[0]["BarcodeHeight"])) ? "100" : Convert.ToString(tbRes.Rows[0]["BarcodeHeight"]));
width = W;
height = H;
AlignmentPositions Align = AlignmentPositions.CENTER;
if (!string.IsNullOrEmpty(Convert.ToString(Convert.ToString(tbRes.Rows[0]["BarcodeAlign"]))))
{
switch (Convert.ToInt32(Convert.ToString(Convert.ToString(tbRes.Rows[0]["BarcodeAlign"]).Trim().ToLower())))
{
case 2: Align = AlignmentPositions.LEFT; break;
case 3: Align = AlignmentPositions.RIGHT; break;
default: Align = AlignmentPositions.CENTER; break;
}
BarcodeAlign = Convert.ToInt32(Convert.ToString(Convert.ToString(tbRes.Rows[0]["BarcodeAlign"]).Trim().ToLower()));
}
TYPE type = TYPE.UNSPECIFIED;
if (!string.IsNullOrEmpty(Convert.ToString(tbRes.Rows[0]["BarcodeFont"])))
{
switch (Convert.ToInt32(Convert.ToString(tbRes.Rows[0]["BarcodeFont"]).Trim()))
{
case 1: type = TYPE.UPCA; break;
case 2: type = TYPE.UPCE; break;
case 3: type = TYPE.UPC_SUPPLEMENTAL_2DIGIT; break;
case 4: type = TYPE.UPC_SUPPLEMENTAL_5DIGIT; break;
case 5: type = TYPE.EAN13; break;
case 6: type = TYPE.JAN13; break;
case 7: type = TYPE.EAN8; break;
case 8: type = TYPE.ITF14; break;
case 9: type = TYPE.Codabar; break;
case 10: type = TYPE.PostNet; break;
case 11: type = TYPE.BOOKLAND; break;
case 12: type = TYPE.CODE11; break;
case 13: type = TYPE.CODE39; break;
case 14: type = TYPE.CODE39Extended; break;
case 15: type = TYPE.CODE93; break;
case 16: type = TYPE.LOGMARS; break;
case 17: type = TYPE.MSI_Mod10; break;
case 18: type = TYPE.Interleaved2of5; break;
case 19: type = TYPE.Standard2of5; break;
case 20: type = TYPE.CODE128; break;
case 21: type = TYPE.CODE128A; break;
case 22: type = TYPE.CODE128B; break;
case 23: type = TYPE.CODE128C; break;
case 24: type = TYPE.TELEPEN; break;
case 25: type = TYPE.FIM; break;
default: MessageBox.Show("Please specify the encoding type."); break;
}
BarcodeFont = Convert.ToInt32(Convert.ToString(tbRes.Rows[0]["BarcodeFont"]).Trim());
}
try
{
if (type != TYPE.UNSPECIFIED)
{
if (string.IsNullOrEmpty(Convert.ToString(tbRes.Rows[0]["ShowCode"])))
{
b.IncludeLabel = false;
}
else
{
b.IncludeLabel = Convert.ToBoolean(tbRes.Rows[0]["ShowCode"]);
}
ShowCode = b.IncludeLabel;
b.Alignment = Align;
//b.RotateFlipType = (RotateFlipType)Enum.Parse(typeof(RotateFlipType), this.cmbBarcodeRotate.SelectedValue.ToString(), true);
//label alignment and position
switch (Convert.ToInt32(Convert.ToString(tbRes.Rows[0]["NumbersLocation"]).Trim().ToUpper()))
{
case 2: b.LabelPosition = LabelPositions.BOTTOMLEFT; break;
case 3: b.LabelPosition = LabelPositions.BOTTOMRIGHT; break;
case 4: b.LabelPosition = LabelPositions.TOPCENTER; break;
case 5: b.LabelPosition = LabelPositions.TOPLEFT; break;
case 6: b.LabelPosition = LabelPositions.TOPRIGHT; break;
default: b.LabelPosition = LabelPositions.BOTTOMCENTER; break;
}
NumbersLocation = Convert.ToInt32(Convert.ToString(tbRes.Rows[0]["NumbersLocation"]).Trim().ToUpper());
//===== Encoding performed here =====
//barcode.Image = b.Encode(type, this.txtBarcodeTry.Text.Trim(), this.btnForeColor.BackColor, this.btnBackColor.BackColor, W, H);
if (string.IsNullOrEmpty(barcodeText))
{
picItem.Image = b.Encode(type, Convert.ToString(tbRes.Rows[0]["BarcodeText"]).Trim(), W, H);
}
else
{
picItem.Image = b.Encode(type, barcodeText, W, H);
}
BarcodeText = Convert.ToString(tbRes.Rows[0]["BarcodeText"]).Trim();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}

the bar code library for encode function attached with question

How to solve this error please ?