After building some system images (which takes a lot of time), here is what works for me :
- sysimage_build_args =
--strip-metadata
this produce the smallest system image for me (225MB) - sysimage_build_args =
--compile=all --strip-metadata --strip-ir
produce 297MB, --compile=all is important otherwise it does not work. - sysimage_build_args =
--compile=all --strip-metadata --strip-ir
+ filter_stdlibs=true + incremental=false produce 266MB.
Thank you for your help on this.