It looks like a new version of WebP came out a little over a week ago. It also looks like this release supports alpha transparency and lossless encoding. Reproducible: Always Steps to Reproduce: 1. Attempt to emerge media-libs/libwebp Actual Results: Weep upon seeing version 0.1.3 Expected Results: Rejoice upon seeing version 0.1.99
in portage
Thank you very much for the rapid response. :-)