[NiteWave]

can change the build option from "--with-gd=shared" to "--with-gd", and rebuild php ? see if it resolves the issue.

another tip, to narrow down the issue, you can run test program to see if working as expected or giving out any error message. for example, http://php.net/manual/en/function.imagejpeg.php
"Example #1 Outputting a JPEG image"