Twenty Eleven header images 83% smaller
|Reported by:||demetris||Owned by:|
As a further step to the image tweaks I submitted in #17641, I applied lossy compression to the JPEG header images of Twenty Eleven.
As you can see in the linked ZIP archive, there are huge gains to be had at the cost of negligible loss. (The differences are certainly obvious in AB comparisons and I imagine that in many cases they would be easy to ABX too, but that is not very relevant considering the intended use of the images.)
The tool I used was convert from the ImageMagick suite, version 220.127.116.11 (current version in Debian Sid; upstream is currently at 6.7.0). I compressed the images at three different quality levels: 50, 62.5 and 75. As a base I used the tweaked images from #17641, which have had their metadata stripped but are otherwise identical to the originals.
Using quality 50 the total size for the eight headers goes down from 1.917.360 to 327.880 bytes. I submit the results of all three compression levels, along with the original images, for your consideration.
(For my part, I am happy with the result in the q50 images except maybe for one image, lanterns.jpg.)