How to change the path to uploads?

This is possible using the following types of filters to change default paths. It is a solution for advanced users. If you are not, please skip this question.

Path to the root installation directory of WordPress (ABSPATH by default):

add_filter( 'xio_site_root', function( $path ) {
    return ABSPATH;
} );

Paths to directories (relative to the root directory):

add_filter( 'xio_dir_name', function( $path, $directory ) {
    switch ( $directory ) {
        case 'uploads':
            return 'wp-content/uploads';
        case 'webp':
            return 'wp-content/uploads-xio';
        case 'plugins':
            return 'wp-content/plugins';
        case 'themes':
            return 'wp-content/themes';
    }
    return $path;
}, 10, 2 );

Note that the /uploads-xio directory must be at the same nesting level as the /uploads, /plugins and /themes directories.

Prefix in URL of /wp-content/ directory or equivalent (used in .htaccess):

add_filter( 'xio_htaccess_rewrite_path', function( $prefix ) {
    return '/';
} );

For the following sample custom WordPress structure:

...
├── web
    ...
    ├── app
    │   ├── mu-plugins
    │   ├── plugins
    │   ├── themes
    │   └── uploads
    ├── wp-config.php
    ...

Use the following filters:

add_filter( 'xio_site_root', function( $path ) {
    return 'C:/WAMP/www/project/web'; // your valid path to root
} );
add_filter( 'xio_htaccess_rewrite_path', function( $prefix ) {
    return '/';
} );
add_filter( 'xio_dir_name', function( $path, $directory ) {
    switch ( $directory ) {
        case 'uploads':
            return 'app/uploads';
        case 'webp':
            return 'app/uploads-xio';
        case 'plugins':
            return 'app/plugins';
        case 'themes':
            return 'app/themes';
    }
    return $path;
}, 10, 2 );

After setting the filters go to Xilifox -> Xilifox Image Optimizer in the admin panel and click the Save Changes button. .htaccess files with appropriate rules should be created in the directories /uploads and /uploads-xio.