Carol (sorry for being OffTopic again while replying to your request), I searched more and I finally found something :
Basically the support says "Use some proprietary method that no other
browser will understand to get your transparency back in PNG."
Gimp-user mailing list
- Re: [OT] Re: [Gimp-user] Not using PNG transparency Karine Proot
- Re: [OT] Re: [Gimp-user] Not using PNG transparency Carol Spears