How to connect a domain in selectel so that the image path is my site?

Question

Domain Name System

In selestel, it is possible to replace the path https://100000.selcdn.ru/i/1/1.jpg with https://img.mysite.com/1/1.jpg The instructions say:

Before attaching a domain, you need to make a DNS CNAME entry pointing to 100000.selcdn.ru.

What I've done.
I went to cPanel in Zone Editor,
clicked add record,
chose CNAME
in the NAME field, entered 100000.selcdn.ru.
I entered img.mysite.com in the entry field.

But as I understand it, I did something wrong.
Tell me how to fasten it correctly so that https://100000.selcdn.ru/i/1/1.jpg becomes https://img.mysite.com/1/1.jpg

Answer 1

img.mysite.com 14400 IN CNAME 100000.selcdn.ru