I've just posted some changes to the package, and I've written up the
parameter list at http://www.ros.org/wiki/jpeg_streamer

If you don't want to use git, you can download a snapshot of umd-ros-pkg at:

  http://ram.umd.edu/git/?p=umd-ros-pkg.git;a=snapshot;h=HEAD;sf=tgz

 - Ken