Produce better image quality/size combination via php Imagick module

[losangelos]

The current implementation of the WP_Image_Editor abstract class via the php-imagick module has a resize function (thumbnail_image) which uses FILTER_TRIANGLE as resize filter by default and some specific values for sharpening and compressing the uploaded jpg image (resize -> sharpen -> compress).

The currently used combination of values/methods for manipulating the uploaded jpg image can be improved by using a combination which produces jpg images better in quality and considerably smaller in size.

We have created a github page ​https://greenpeace.github.io/planet4-imagestest-results/ where we can compare results produced by 6 different methods.
Method #1 is the default method used by WP currently.
Method #6 produces best quality/size combination among those.

Resize: Lanczos
Sharpening: unsharpMask( Radius 1, Sigma 0.45, Amount 3, Threshold 0 )
Compression: Interlace_Plane
Quality: 60

Will upload diff file soon.

[audrasjb]

Hi @losangelos and welcome to Trac!

Thank you for this ticket, but this issue is already tracked in #40415

You are very welcome to contribute to the existing ticket :)

Cheers,

Jb