Steps to reproduce: 1) Build media-libs/gd without USE="png" 2) Generate graphs with mrtg Results: * All images produced are in gif format * The links to the graph images are generated correctly * The links to sundry images incorrectly have a suffix of ".png" instead of ".gif" I a using mrtg-2.17.4 but the bug probably applies to previous versions too. My suggested workaround is to change the gd dependency so that png support is required:- >=media-libs/gd-1.8.4[png]
Fixed in 2.17.4-r1. Thanks for the report!