I'm pretty new to Ruby and Rails.  I am writing a Rails application
that is meant to be run on a local machine.  It allows the user to
select a bunch of image (jpg, gif, etc)  files from anywhere on their
file system and add them to an album.

The prototype of the is app is going to leave the images where they are
on the disk (and not persist them anywhere else).  I want to write a
controller that can take an image name and location on disk as a
parameter and then serve the file to the user via the WEBrick server so
that the image appears properly in the browser.

Is there any sample code anywhere for opening a binary file and serving
it as jpg (or whatever) to the user?

Regards