You want signature field preview in your ContentBuilder view?
If you have ContentBuilder and BreezingForms integration and you have signature field which needs to be displayed in your ContentBuilder view just copy the following code into the Item wrap code of that element:
<?php $value = '<img src="'.Juri::root(true).'/media/breezingforms/signatures/'.$value.'"/>';?>
If you want to display image of signatures in the Content Template, go to your view > Content Prepare, and copy the following code there:
$items["ITEMNAME"]["value"] = '<img src="'.Juri::root(true).'/media/breezingforms/signatures/'.$items["ITEMNAME"]["value"].'"/>';
Just make sure to change "ITEMNAME" to the correct name of signature item.