A task can first appear in a SHOW THREAD display as soon as it
    is created. A task can no longer appear in a SHOW THREAD display
    if it is terminated or (in the case of an Ada tasking program)
    if its master is terminated. By default, the SHOW THREAD command
    displays one line of information for each task selected.

    When you specify the /IMAGE qualifier, the debugger first does a
    SET IMAGE command for each image that has debug information (that
    is, it was linked using the /DEBUG or /TRACEBACK qualifier). The
    debugger then displays the image name for each active call on the
    calls stack. The output display has been expanded and displays
    the image name in the first column.

    The debugger suppresses the share$image_name module name, because
    that information is provided by the /IMAGE qualifier.

    The SET IMAGE command lasts only for the duration of the SHOW
    THREAD/CALLS/IMAGE command. The debugger restores the set image
    state when the SHOW THREAD/CALLS/IMAGE command is complete.

    Related commands:

       DEPOSIT/TASK
       EXAMINE/TASK
       (SET, SHOW) EVENT_FACILITY
       SET TASK|THREAD