Serialization of 'Symfony\Component\HttpFoundation\File\UploadedFile' is not allowed
Little extra precision in DOZ words :
It's better to implement \Serializable in your Image (or File, or @Vich\Uploadable) Entity instead of implement \Serializable on User Entity because you probably break login in this case.
If you are using VichUploader like me don't add \Serializable on your User Entity and add it on your @Vich\Uploadable (Image or File) Entity and add the two methods :
/** @see \Serializable::serialize() */public function serialize(){ return serialize(array( $this->id, $this->image, ));}/** @see \Serializable::unserialize() */public function unserialize($serialized){ list ( $this->id, $this->image, ) = unserialize($serialized, array('allowed_classes' => false));}