-dpng gives "invalid command"

[John B. Thoo]

Hi, everyone.

I can save a plot to EPS by

   print ("foo.eps", "-deps")

but when I try to save a plot to PNG by

   print ("foo.png", "-dpng")

I get a run of errors like


gnuplot> e
          ^
          line 0: invalid command


and no plot is saved.

What am I doing wrongly?

I'm using Octave 3.0.5 and gnuplot 4.2 patchlevel 5 in an X11 xterm  
window in Mac OS X 10.4.11.

Thanks.

---John.