We are using some other barcode generating solutions and our customers are used to labels below the barcode. As far as I've seen, you are generating labels above the barcode.
Is is possible to change the label position?
BarcodeSettings settings = new BarcodeSettings();
settings.Type = BarCodeType.Code128;
settings.Data = "123456789";
settings.ShowTextOnBottom = true;
BarCodeGenerator generator = new BarCodeGenerator(settings);
var image = generator.GenerateImage();
image.Save("barcode.png");