Problems with gnuplot and jpg output

[ws]

Hi all

I just installed gnuplot-4.2.5 and octave-3.0.5 in my home directory on a 
Fedora machine from source.

I would like to plot to jpegs (or png's), which I will reference in webpages.  
I could also deal with eps, though I will convert it after.  In gnuplot, I 
would first "set terminal png" and then do all my plotting; I don't know how to 
do this in octave.

I try:
octave> gnuplot_binary('/home/wsprague/gnuplot-4.2.5/bin/gnuplot')
octave> plot(1:4)

I get: 

gnuplot> set terminal x11 enhanced title "Figure 1"
                      ^
         line 0: unknown or ambiguous terminal type; type just 'set terminal' 
for a list


gnuplot> plot "-" using ($1):($2) axes x1y1 title "" with lines linestyle 1 ;
              ^
         line 0: use 'set term' to set terminal type first


gnuplot> 1 1
         ^
         line 0: invalid command


gnuplot> 2 2
         ^
         line 0: invalid command


gnuplot> 3 3
         ^
         line 0: invalid command


gnuplot> 4 4
         ^
         line 0: invalid command


gnuplot> e
         ^
         line 0: invalid command

Any help is appreciated!