My conclusion after current issue research is so, that doing any kinds of file deletion on ORM postRemove is wrong because ORM events happen inside implicit begin/commit transaction of UnitOfWork and does not guarantee that entity will be really physically removed from db (e.g. FK constraints issues). That actually said in Doctrine ORM events doc page. Depending on the context i see next possible solutions:

1. Image removal can be done on Sylius resource post_delete event of the image(s) owning entity. Suitable for the cases of image aware resources deletion like product or taxon, when we for sure want delete all related pictures.
2. On Doctrine ORM postRemove use some special service for postponed image file deletion . So here we just add image-entity to service. Later on, using listener over Doctrine postFlush event we access that service and ask him to do actual removal of all accumulated images (post-flush event is the last one always and happens AFTER real implicit transaction was committed). This is generic case solution which seems to be working without any specific context knowledge (for explicit image removal from ORM in own code, via cascading entity operations on relations, etc).

Any chances the issue fix will appear in 1.1?

Closing in favour of #9906