Wrong thumbnails created - transparency

[pavelevap]

When I upload attached .png picture, wrong thumbnails are created (black and white lines etc.) It is probably related to transparency...

[dd32]

See Also: ​http://www.php.net/manual/en/function.imagecopyresampled.php#93166

basically, the GD resize functions do not handle transparency.

Setting to 3.0 at present, This is unlikely to be patched for a 2.9 release.

[apeatling]

I'm almost certain that this is because all thumbnails are created as JPG's regardless of their original file type, but I'll start digging to confirm.

[apeatling]

I take that back, my png tests seemed to thumbnail fine, but I could reproduce the issue with the attached image.

[nacin]

Related? #11671

[apeatling]

@nacin - Yes, seems to be the same problem, it's to do with the color profile of the image.

It's using a "20% Dot Gain" profile. If I open the image in Photoshop and remove the profile then the thumbnail works fine.

[apeatling]

Punt to 3.1? This should be fixed once #11671 is dealt with.

[scribu]

Actually, I'm just going to mark this as a dup of #11671