I did something similar- a web application for online employer picture
directory along with dynamic graphical output of the desk locations
throughout the company (using the GD package).
I kept the pictures in a separate directory and used links in the
database. I set up a DB trigger that took care of the respective
picture if an employer left. It worked great and was fantastic from a
performance perspective.
The only reason I could come up with keeping images in the DB as BLOBs
is if you developed a specialized function that would do actual image
analysis on the pictures themselves. For example, flagging certain
images after weeding out faces of terrorists in a picture of a crowd
of random people. But what do I know, I don't work at the Department
of Homeland Security :-)
Jared