Migrating an application from eZ Platform 1.13 to Ibexa OSS 3.3.1, I found out that create  images variations is slower and require more memory : from old version to the new one.

v1.13 is still in production (running on debian 9 with offical paquets), since there is that issue on image generation, I can't deploy v3.3.1

Generaly: generating a sample page is jumping from 12s (with v1.13) to 20s (with 3.3.1) : with same content and same code

I am focusing on image because of the following :

and with load tests, PHP process are eating up to 2Go memory! (max memory is set to 256Mo in cli/fpm PHP config ...) 

most of varations use thumbnail filter, here an example :

diaporama_full_screen_mobile_20190820:
    filters:
        - { name: thumbnail, params: { size: [720, null], mode: outbound, filter: "lanczos" } }
    post_processors:
        jpegoptim: { strip_all: true, quality: 80, progressive: true }
        optipng: { strip_all: true, level: 1 }