https://bugs.winehq.org/show_bug.cgi?id=47113
--- Comment #22 from Olivier F. R. Dierick o.dierick@piezo-forte.be --- Hello,
Can you create your own sample transparent 32-bit rgba BMP with gimp or imagemagick and try to display that file with firefox or chrome (compare Windows versus Wine)?
Does it reproduce the issue? If the issue can be reproduced with those applications then the bug would be valid.
Just don't attach or link to questionable applications or private copies of files from such applications. Don't even mention the questionable application.
See How to create BMPv3 format there: http://www.imagemagick.org/Usage/formats/#bmp
Regards