How Mod Rewrite A Directory Or Folder

sir, i followed your tutorial on how to do mod rewrite module in apache,

the tutorial shows how to do it for a file, but how about if i want to do it to a directory.

for example, i want all the files with the url of : pictures to go to my gallery directory like this:

from:
(http://www.example.com/pictures/)
/var/www/mywebs/example/public/pictures/

to:
(http://www.example.com/pictures/)
/var/www/mywebs/example/public/gallery/

so as you can see, i want all the traffic for the pictures directory to go to the gallery directory.

thanls