Closed Bug 549244 Opened 12 years ago Closed 11 years ago

Alpha channel problem for PNG graphic on Linux (x86_64?) systems


(Firefox :: General, defect)

Not set





(Reporter: r.michell, Unassigned)




(Whiteboard: [CLOSEME 2011-1-30])

User-Agent:       Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6
Build Identifier: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6

Viewing the above website:, the level-1 tabs comprising a CSS background-image ( appear washed-out and faded. Looking at the same site in the same FF version on Windows XP, everything appears as it should.

I checked with a colleague on a different Linux computer (Not sure what flavour or architecture, sorry) and he had the same problem.

Accessing the image directly in Linux+Firefox 3.6+, it doesn't show at all. Accessing the image directly in Windows+Firefox 3.6+, it appears as it should.

The image was originally generated as a PNG8, using a transparent background and with Alpha Transparency, using Macromedia Fireworks v8.0 on Windows XP SP3.

If I remove the alpha transparency, export it as PNG8 and view it in FF, I can see the image, no probs. Only when I re-add the transparency (Tried using greyscale, Adaptive and Web Adaptive palette) does the image "disappear" again when viewed directly in the browser.

I suspected it could be a Linux library issue on my system, but don't know enough where to look and would have thought FF might be able to work in most "common" Linux flavours?

Tested using current Firefox (v3.6) and firefox-3.7a2pre.en-US.linux-x86_64 (differs from 'Build Identifier' as noted above) on CentOS 5.2 x86_64.

Reproducible: Always

Steps to Reproduce:
1. Visit using FFv3.6+ on Windows XP SP3 --> You can see an image (a CSS-sprite background-image)
2. Visit using FFv3.6+ on Linux, x86_64, CentOS v5.2 (possibly others) --> No image displayed.
3. Visit the site whre bg image is used: (Main navigation) image appears all washed-out.
Actual Results:  
Images appear washed out on Linux, normal on Windows.

Expected Results:  
Display the raw PNG8 graphic at correctly.
Reporter, are you still seeing this issue with Firefox 3.6.13 or later in safe mode? If not, please close. These links can help you in your testing.

You can also try to reproduce in Firefox 4 Beta 8 or later, there are many improvements in the new version,
Whiteboard: [CLOSEME 2011-1-30]
Fantastic! Upgraded to 3.6.13 on CentOS 5.2. Images appear as they should.

Good work Firefox team!
Closed: 11 years ago
Resolution: --- → FIXED
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