"We plan to add support for a transparency layer, also known as alpha channel in a future update." http://blog.chromium.org/2010/09/webp-new-image-format-for-w

"We plan to add support for a transparency layer, also known as alpha channel in a future update." http://blog.chromium.org/2010/09/webp-new-image-format-for-web.html http://blog.chromium.org/2010/09/webp-new-image-format-for-w...