Private files are great but they are a huge resource hog. In certain scenarios, lower-resolution versions of the pictures are absolutely fine to be public, only high resolution originals need to be protected. In this case you can use Drupal's private file handling as it is and the following simple trick to make a style public.
In your Drupal root:
mkdir -p system/files/styles
ln -s /absolute/path/to/the/directory/containing/the/private/files/styles/stylename
Apache will see now the "private" file as a real filename (because Drupal's htaccess contains
Options +FollowSymLinks) and happily serve the file without going through Drupal.
Commenting on this Story is closed.