A color specified as transparent using a tRNS chunk, is treated as opaque, please see the attached test app.

Although, according to the PNG spec, tRNS belongs to ancillary chunks and could be ignored by a decoder, it's extremely important for WebNode to display such images correctly, because this is the last issue preventing WebNode from passing the Acid2 browser test (see http://www.webstandards.org/action/acid2/), what is a PRD requirement for Presidio. All less-or-more known image viewers and web browsers support tRNS transparency already. That's the reason why I'm raising this issue to Critical.