License files GPL_LICENSE.txt and lgpl_v21.txt shouldn't be installed. netpbm.html is installed twice, in /usr/share/doc/${PF} and in the html subdir.
Clean up doc install; thanks! http://sources.gentoo.org/media-libs/netpbm/netpbm-10.51.00-r1.ebuild?r1=1.3&r2=1.4
sorry, correct link is: http://sources.gentoo.org/media-libs/netpbm/netpbm-10.51.00-r1.ebuild?r1=1.2&r2=1.3