<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_URI} .*wp-content/uploads/.(jpg|jpeg|png|gif)$ [NC] !-f
#вариант который должен работать, но нет
#RewriteRule ^/wp-content/uploads/(....)/(..)/(..)(.*)$ "testp/$3/$3$4" [L]
#еще 1
#RewriteRule ^/wp-content/uploads/(....)/(..)/(..)(.*)$ "/testp/$3/$3$4" [L]
#и еще
#RewriteRule ^/wp-content/uploads/2019/01/(..)(.+)$ "/testp/$1/$1$2" [L]
#вариант "и даже так нет?"
RewriteRule ^/wp-content/uploads/2019/01/01512b3c874f00c1266e66b54a51bc20.jpg$ "/testp/01/01512b3c874f00c1266e66b54a51bc20.jpg" [L]
</IfModule>#IMG Mapping by symlink#
<IfModule mod_rewrite.c>
RewriteEngine On
#RewriteBase /
#RewriteCond %{REQUEST_URI} ^/wp-content/uploads/(\d{4})/(\d{2})/(..)(.*)\.(jpg|jpeg|png|gif)$ [NC]
#RewriteRule (.*) /testp/$3/$3$4.$5
#RewriteCond %{REQUEST_URI} .*wp-content/uploads/(....)/(..)/.(jpg|jpeg|png|gif)$ [NC] !-f
RewriteCond %{REQUEST_URI} .*wp-content/uploads/.(jpg|jpeg|png|gif)$ [NC] !-f
#                                                         1    2   3  4
RewriteRule ^/wp-content/uploads/(....)/(..)/(..)(.*)$ "/testp/$3/$3$4"
#RewriteRule ^/wp-content/uploads/(....)/(..)/(..)(.*)$ "testp/$3/$3$4"
</IfModule>
#/#root@159:~# df -h
Filesystem      Size  Used Avail Use% Mounted on
udev             32G     0   32G   0% /dev
tmpfs           6.3G  2.1M  6.3G   1% /run
/dev/sda3       437G  346G   69G  84% /
tmpfs            32G   30M   32G   1% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs            32G     0   32G   0% /sys/fs/cgroup
/dev/sda2       488M   80M  384M  18% /boot
tmpfs           6.3G   20K  6.3G   1% /run/user/0
/dev/sdb        469G  295G  151G  67% /mnt/ssd
tmpfs           6.3G   16K  6.3G   1% /run/user/125
/dev/sdc        3.6T  3.3T  186G  95% /mnt/hdd
tmpfs           6.3G     0  6.3G   0% /run/user/1000function img_get_mime_type($file)
{
    $mime_types = array("gif" => "image/gif", "png" => "image/png", "jpeg" => "image/jpg", "jpg" => "image/jpg",);
    $file_exp = explode('.', $file);
    $extension = strtolower(end($file_exp));
    if (array_key_exists($extension, $mime_types)) {
        return $mime_types[$extension];
    }
    return "application/force-download";
}
    $mime = img_get_mime_type($image);
    header('Content-type: ' . $mime);
    fpassthru(fopen($image, 'rb'));
RewriteRule (.*) "/testp/$3/$3$4.$5" [L]