Why doesn't image compression work?

Question

PHP

I welcome everyone.
Updated php to 5.4, installed GD. I downloaded files from adaptive-images.com , uploaded them, created a folder for the cache, inserted the code into html and the images themselves are not compressed. How to check at what stage the error is, maybe GD is not working? The installation instructions couldn't be easier, but I can't understand why it doesn't work...
Note: everything is in one place, index.html, php file, image, folder, etc...

Answer 1

insert at the beginning of the script at least

ini_set("display_errors", 1);
error_reporting(E_ALL);

see errors

Answer 2

In short ... I have nginx handling static, so I just have to figure out why inserting this:
location assets {
}
location ai-cache {
}
location / {
rewrite \.(?:jpe?g|gif|png)$ /adaptive -images.php
}
doesn't work....
Pictures don't open, they become 12 kilobyte miracle, they are sent to php file and of course the result is zero