Open an image allowing modification of any header items HDR_MOD
This subroutine may be used to obtain modification access to more than one image at a time by using
multiple parameter names. Multiple parameter names are provided as a comma separated list (i.e.
’
IN1,IN2,IN3’
).
This subroutine should only be used in programs that only modify header items. If you intend to also modify the image data then use an ??x]]IMG_MOD[n][x] subroutine.