[wp-trac] [WordPress Trac] #30402: WordPress does not respect the bit-depth of the original image when resizing

[WordPress Trac]

#30402: WordPress does not respect the bit-depth of the original image when
resizing
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 Reporter:  qdinar        |       Owner:
     Type:  defect (bug)  |      Status:  new
 Priority:  normal        |   Milestone:  Awaiting Review
Component:  Media         |     Version:  3.9.2
 Severity:  normal        |  Resolution:
 Keywords:  needs-patch   |     Focuses:
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Comment (by qdinar):

 {{{
 // Limit the  bit depth of resized images to 8 bits per channel.
 if ( 8 < $this->image->getImageDepth() ) {
 $this->image->setImageDepth( 8 );
 }

 }}}
 without additional conditions - it is in try {} in function
 thumbnail_image {} - i think this is probably not very well because
 probably jpeg resizes to jpeg with 24 bit rgb image, and only indexed
 images should be resized to indexed images. but i do not know and think
 probably setImageDepth ( 8 ) sets 8 bit indexed image. anyway , 8 bit is
 probably too small for jpeg or not supported, and, if it is 8 bit rgb
 image, it is also not optimal, probably 8 bit indexed image is better,
 because it can better fit needed colors.

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Ticket URL: <https://core.trac.wordpress.org/ticket/30402#comment:16>
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