If you ever happen to need to prevent files from being downloaded from a particular folder, you can add this web.config to that folder:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<system.webServer>
<handlers>
<add name="Disable File Downloads" path="*" verb="*" type="System.Web.HttpNotFoundHandler" />
</handlers>
</system.webServer>
</configuration>
I have tested this with IIS 10, though I believe it works with most modern versions of IIS (say, IIS 7 and greater).
Much of this was derived from this Stack Overflow post: https://stackoverflow.com/a/27947061/2052963
