Issue "Header set" in .htaccess not working with "Smart static files processing" enabled

[JoeShmoe]

I want to add a HTTP header to images in a certain directory.
However when adding

Header set test 1

to .htaccess in the directory, the the header isn't added to the files.

Only after disabling "Smart static files processing" the header shows up.

I could just leave it disabled, but Plesk suggests disabling is "only for troubleshooting".
Tested on two servers (centos and ubuntu) with the latest Plesk.

 

[mow]

1. "Smart static files processing" means nginx processes the requests without passing it along to apache, serving the files itself directly.
2. nginx does not use .htaccess. Only Apache does.
3. So for this to work, you'll need further nginx directives, not .htaccess.