-------------------------------------------
var,funct (left-click): read mgz (or COR dir)
  set inoutim <CORdir *or* mgz>
  read_images
-------------------------------------------

The "R" button re-reads the startup set of
editable images (COR dir or .mgz file), warning
if edited but not saved.

If a different imageset than the startup one is
specified in the entry, that will be read in
instead.

If a second set of images read ("R" button to
read imageset in "im2:" entry), COMPARE can be
used to blink between first and (non-editable)
second.

The images that have been read in are not
saved/overwritten until "SAVE IMGS" is clicked.
