An image data manipulation system is described in which users located remotely
from an image data storage library may participate in a collaborative image data
rendering and evaluation session. The system includes the exchange of state parameters
between the client computer of a user controlling the image rendering, the session
driver, and a server computer which relays updated state parameters to other client
computers participating in a session. The state parameters are used to update the
view on each users computer to keep all the displays of the participants in synch
with that of the session driver. The server processes extensive image rendering
task for which the remote clients are not equipped and transmits newly-processed
image data to the clients as appropriate. One embodiment for educational applications
utilizes pre-stored image data sets which eliminates the need to transmit large
blocks of image data over a network during a collaborative session.