Enabling Gzip compression guidance needed

Hi, Guys

I am following this tutorial https://www.digitalocean.com/community/tutorials/how-to-add-the-gzip-module-to-nginx-on-ubuntu-16-04, but when testing, the output is different. It seems something is not working for me.

After following the steps in the tutorial, when testing:

curl -H "Accept-Encoding: gzip" -I http://localhost/test.jpg

The output is:

HTTP/1.1 301 Moved Permanently
Server: nginx/1.10.3 (Ubuntu)
Date: Wed, 04 Sep 2019 18:33:30 GMT
Content-Type: text/html
Content-Length: 194
Connection: keep-alive
Location: https://radha.org.br/test.jpg

So the header Content-Encoding: gzip is not appearing.

Another question is that i have two wordpress websites in my droplet. This configuration will impact the two of them or i have to configure each site separatedly for Gzip compression to work?

Anyway, i followed the tutorial until its end and after that i gave a reboot in my droplet, but still it seems hothing has changed.

Thank you so much for taking care.