It really depends on your Apache ".htaccess configuration". If ".htaccess support" is enable, most likely, the .htaccess file in your Gallery folder. It could also be the .htaccess at the web root of your site.
I personally disable .htaccess support and include all my .htaccess directives in the global Apache configuration file using an include statement. .htaccess directives in your global Apache configuration file are only loaded once versus at each file access.

If I see some interest in this I might write an article with more details.

Cheers,
C