Command explanations : This switch is used to avoid the configuration routine asking for confirmation of the directories to install to (which we pass using switches to configure anyways). --with-DIR_MAN=/usr/share/man: This is used because despite the fact we pass --prefix=/usr, the configure routine tries to install the man pages in /usr/local/man instead of the correct place. --with-ZIP=yes: This enables support for the handling of TIFF images with deflate-encoded data. --with-JPEG=yes: Use this switch to enable support for the handling of TIFF images with JPEG-encoded data.