Version 4.0&4.2 ---terminal PDF, JPEG not be accessible in WinXP environment

[<hi...@gm...>]

Hello,

When I set that two terminals, it showed:

*gnuplot> set term jpeg
                  ^
         unknown or ambiguous terminal type; type just 'set terminal' for a
list*
**
*gnuplot> set term pdf
                  ^
         unknown or ambiguous terminal type; type just 'set terminal' for a
list*
**
and I typed *set term:*
there are no Jpeg and pdf in the*  Available terminal types.*
**
Is there something I need to install to access these two terminals?
I have tried both version 4.0 and 4.2, same problem.

Thanks!
Todd Sun
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