I have done something similar to this, though I would caution that I was told the method I used is not officially supported by Inductive Automation and there’s no guarantee that this would work in future versions of the software.
You can reference directories and files contained within the /webserver/webapps/main directory of your Ignition install directly from a web browser by simply appending the file name to the address of your Ignition gateway. For example, if you placed an mp3 file named ‘test_sound’, you would be able to hear the mp3 by pasting ‘localhost:8088/test_sound.mp3’ into a web browser on the machine where your Ignition gateway is installed. In order to map files from a network drive here, I would suggest creating a symbolic link to the directory in the network drive in that location. That way, since this is an unsupported “feature” of Ignition, if the /webserver/webapps directory were ever to be overwritten (say, during the installation of a new version of Ignition) your actual data in the network drive would remain untouched and you would simply need to re-establish the symbolic link to the network directory in order to restore access to those files from within SCADA.