gtk+ doesn't install itself

I'm trying to install gtk+2.1.14.7. As 'configure' didn't find libjpeg, I downloaded and installed jpegsrc.v6b.tar.gz from http://www.ijg.org/.
But 'configure' of gtk give me this error:
 configure: WARNING: *** JPEG loader will not be built (JPEG library not found) ***
 configure: error:
 *** Checks for JPEG loader failed. You can build without it by passing
 *** --without-libjpeg to configure but some programs using GTK+ may
 *** not work properly
In fact /usr/local/lib/libjpeg* doesn't exist.
The output of "make install" of jpeg-6b follows:
 dario@dario-lubuntu:~/downloads/jpeg-6b$ make -n install
 /usr/bin/install -c cjpeg /usr/local/bin/cjpeg
 /usr/bin/install -c djpeg /usr/local/bin/djpeg
 /usr/bin/install -c jpegtran /usr/local/bin/jpegtran
 /usr/bin/install -c rdjpgcom /usr/local/bin/rdjpgcom
 /usr/bin/install -c wrjpgcom /usr/local/bin/wrjpgcom
 /usr/bin/install -c -m 644 ./cjpeg.1 /usr/local/man/man1/cjpeg.1
 /usr/bin/install -c -m 644 ./djpeg.1 /usr/local/man/man1/djpeg.1
 /usr/bin/install -c -m 644 ./jpegtran.1 /usr/local/man/man1/jpegtran.1
 /usr/bin/install -c -m 644 ./rdjpgcom.1 /usr/local/man/man1/rdjpgcom.1
 /usr/bin/install -c -m 644 ./wrjpgcom.1 /usr/local/man/man1/wrjpgcom.1
 dario@dario-lubuntu:~/downloads/jpeg-6b$
Where is libjpeg.a?

Give me a suggestion!