[tex-eplain] Prevent page break

[Karl Berry]

The point of that \vbox was to fake the size of the image.  E.g., you
could say \vbox to 0pt{...\vss} and TeX will think it takes up zero
space on the page.  There's no limit, per se, on the size, but if you
make it the size of a whole page, then TeX will think the page is full
and go ahead with the break.  So that doesn't make sense to do.

If you want to actually change the size of a typeset image, you need to
use width= or height= (or whatever) to \includegraphics, or \epsfxsize
with epsf.tex, or whatever equivalent, depending on how you're including
it.  Maybe that's what you need to do ... still not sure what your
situation really is ... -k