For all Joomla 3+ templates built using the Zen Grid Framework v4 (any theme after October 2014) please refer to the Zen Grid Framework v4 documentation.
The Zen Grid Framework has an IE6 PNG Fix built right into its core so you dont have to mess around with 3rd party scripts or plugins. The PNG Fix uses the DD Belated PNG Fix and works in the following way. It will transform any png images that have a transparent background and render them with those backgrounds in IE6. In order to add any new rules to your template you simply need to add the css class with the transparent background.
As you can see in the screenshot below its as easy as naming each class and separating them with a comma. Please note that this script can provide varied results especially if the png image is sitting on top of another css class that also uses a png image as its background.