The SET IMAGE command builds data structures for one or more
    specified images but does not set any modules within the images
    specified.

    The current image is the current debugging context: you have
    access to symbols in the current image. If you specify only one
    image with the SET IMAGE command, that image becomes the current
    image. If you specify a list of images, the last one in the list
    becomes the current image. If you specify /ALL, the current image
    is unchanged.

    Before an image can be set with the SET IMAGE command, it must
    have been linked with the /DEBUG or /TRACEBACK qualifier on the
    DCL command LINK. If an image was linked /NOTRACEBACK, no symbol
    information is available for that image and you cannot specify it
    with the SET IMAGE command.

    Definitions created with the DEFINE/ADDRESS and DEFINE/VALUE
    commands are available only when the image in whose context they
    were created is the current image. When you use the SET IMAGE
    command to establish a new current image, these definitions are
    temporarily unavailable. However, definitions created with the
    DEFINE/COMMAND and DEFINE/KEY commands are available for all
    images.

    Related commands:

       SET MODE [NO]DYNAMIC
       (SET,SHOW,CANCEL) MODULE
       (SHOW,CANCEL) IMAGE