gnuplot does not save image correctly in PNG ! Help !

[Franklin Anderson]

Hi everybody !!

i have this script in gnuplot:

---

set grid ytics
set grid xtics

set xlabel "foobar"
set ylabel "acme"

set xtics rotate

set xdata time
set timefmt '%Y-%m-%d, %H:%M%S'
set format x '%Y-%m-%d %H:%M%S'

set datafile sep ','

plot 'data.txt' u 1:3 with linespoints lw .2 pointsize .1 pointtype 7 linecolor 7 title "UDP LATENCY"

---

when I run it generates a beautiful graph

but when i configure to save the graph in a png file

---

set terminal png size 1024, 768
set output 'image.png'

set grid ytics
set grid xtics

set xlabel "foobar"
set ylabel "acme"

set xtics rotate

set xdata time
set timefmt '%Y-%m-%d, %H:%M%S'
set format x '%Y-%m-%d %H:%M%S'

set datafile sep ','

plot 'data.txt' u 1:3 with linespoints lw .2 pointsize .1 pointtype 7 linecolor 7 title "UDP LATENCY"

---

I have result this graph

Very Different !!! :(

But if i do this:

generates the correct graph ! :|

need to generate the graph via script exactly the same as graph 1 or 3!!! Any Tips?!