[SE] Converting transparent PNG to GIF loses transparency

anonymous_user · Post by **anonymous_user** » Wed Jan 02, 2008 6:44 pm

<-- Moderator's note: This topic has been split off from “XnView Shell extension”. -->

When I use the shell extension to convert a transparent PNG to GIF, it loses the transparency and gets a black background. Any ideas?

Post by **XnTriq** » Wed Jan 02, 2008 8:50 pm

anonymous_user wrote:When I use the shell extension to convert a transparent PNG to GIF, it loses the transparency and gets a black background. Any ideas?

Loading GIF, removing transparency, saving JPG

anonymous_user · Post by **anonymous_user** » Wed Jan 02, 2008 9:26 pm

Sorry for mentioning earlier, but I dont want to change the background color. I want it to stay transparent. Last I checked GIF does support transparency.

Post by **XnTriq** » Wed Jan 02, 2008 11:40 pm

Converting truecolor PNG images to GIFs will inevitably result in loss of transparency, because the color depth has to be reduced to 8-bit in the process.

When an 8-bit PNG is converted to GIF format on the other hand, the transparency index of the source image's palette is maintained.

anonymous_user · Post by **anonymous_user** » Sat Jan 05, 2008 1:43 pm

Paint.NET lets me save PNGs as GIF without losing transparency. I guess XnView doesnt?

Post by **xnview** » Sun Jan 06, 2008 5:01 pm

anonymous_user wrote:Paint.NET lets me save PNGs as GIF without losing transparency. I guess XnView doesnt?

It's impossible to keep 24bits with alpha in gif format, you don't choose a transparency index?

Post by **XnTriq** » Sun Jan 06, 2008 11:15 pm

Programs like Photoshop/ImageReady and Fireworks are capable of reducing an images bit depth from truecolor to indexed color without loss of transparency.
But these are full-fledged image editors.