Syntax: IMAGE file
or      IMAGE file xmin xmax ymin ymax
or      IMAGE ( nx, ny )
or      IMAGE ( nx, ny ) xmin xmax ymin ymax
or      IMAGE CURSOR
or      IMAGE CURSOR WORD1 WORD2 WORD3
or      IMAGE DELETE

   Read an image from file "file", optionally specifying the range of
coordinates covered by the data values. If you do not specify them
they will be taken to be "0 nx-1 0 ny-1" where nx and ny are the
dimensions of the image. If you use (nx,ny) instead of a filename an
empty image of those dimensions is created; it may be filled by saying
SET image(x,y) = values.

   IMAGE CURSOR is identical to CURSOR (q.v.), except that it also
gives the value of the image at the cursor; IMAGE CURSOR WORD WORD WORD
is equivalent to CURSOR WORD WORD, but it also generates a vector of
image intensities.

   IMAGE DELETE will forget the current image and levels.

   The format of the data file is specified by a `filecap' file, which
must be defined in your .sm file. The IMAGE command looks in this
file for the value of the variable `file_type'. See the manual for
details. Common values are `C' (for C files), `unix' (For fortran
unformatted files under unix) and `vms_var' or `vms_fixed' for
unformatted fortran files under VMS. In all of these cases, the file
begins with two integers giving the dimension of the array, followed
by the data. For Fortran under VMS, you MUST use a recl=512 (i.e.
2048by) (file_type vms_var), or specify `format=fixed' in your open
statement and some record length (file_type vms_fixed), or change the
filecap file. See the manual for examples.

   See also ARITHMETIC for extracting cross-sections of an image, and DEFINE
for defining variables from an image header.