[boost] [tweener] How to copy image files in documentation

Hi, I wrote the documentation of Boost.Tweener in boostbook format. I have references to some images in the documentation but they are not copied in the target html directory when I type bjam html How can I make the image directory to be automatically copied in the target directory of the generated documentation? Since I am not familiar with the build process of Boost yet, I would accept a reason not to do this as an answer :) Regards, Julien Jorge