I think this is an old question. But since firebird sql undergo many
changes, may be the answer would have difference.

I have an web application with about 100,000 images average 50KB. What is
the performance difference for save the images in blob or in a file system
directory ?

Sorry, it is my first web application so I have no experience on this area.
I think it is more easy to get the image if save in a directory. Save the
images in db is more easy to manage.

Any comment is welcome.