Either set height property in codebehind .cs file

BCSBarcodeCtrl1.Height = 100;

Or add a tag directly

< img src="barcodesoft.ashx?s=code39&h=100

< img src="barcodesoft.ashx?s=code39ext&h=88

int height
Default value of height property is 71.
You can set it to be any proper integer.
This property sets bar code height.

You can also setup height property through URL by setting "h":
<img src="Barcodesoft.ashx?s=code39&TEXT=1234&h=100>