Upload avec le bundle Vich

Bonjour,

Je suis sous symfony 4.2.0, j'essaye d'utiliser le bundle VichUploader mais lors de l'édition j'obtiens une erreur :

Expected argument of type "string", "NULL" given at property path "image".

Alors que pourtant j'ai vraiment bien suvi toute la configuration je comprends pas :(

Mon Entity :

<?php

namespace App\Entity;

use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\HttpFoundation\File\File;
use Vich\UploaderBundle\Mapping\Annotation as Vich;

/**
 * @ORM\Entity(repositoryClass="App\Repository\WorkRepository")
 * @Vich\Uploadable()
 */
class Work
{
    /**
     * @ORM\Id()
     * @ORM\GeneratedValue()
     * @ORM\Column(type="integer")
     */
    private $id;

    /**
     * @Vich\UploadableField(mapping="works_image", fileNameProperty="image")
     * @var File|null
     */
    private $imageFile;

    /**
     * @ORM\Column(type="string", length=255)
     */
    private $title;

    /**
     * @ORM\Column(type="string", length=255, nullable=true)
     */
    private $subTitle;

    /**
     * @ORM\Column(type="string", length=255)
     * * @var string|null
     */
    private $image;

    /**
     * @ORM\Column(type="datetime")
     */
    private $created_at;

    /**
     * @ORM\Column(type="string", length=255, nullable=true)
     */
    private $link;

    /**
     * @ORM\Column(type="datetime")
     */
    private $updated_at;

    public function __construct()
    {
        $this->created_at = new \DateTime('now');
    }

    public function setImageFile(?File $image = null): void
    {
        $this->imageFile = $image;

        if (null !== $image) {
            $this->updated_at = new \DateTime('now');
        }
    }

    public function getImageFile(): ?File
    {
        return $this->imageFile;
    }

    public function getId(): ?int
    {
        return $this->id;
    }

    public function getTitle(): ?string
    {
        return $this->title;
    }

    public function setTitle(string $title): self
    {
        $this->title = $title;

        return $this;
    }

    public function getSubTitle(): ?string
    {
        return $this->subTitle;
    }

    public function setSubTitle(?string $subTitle): self
    {
        $this->subTitle = $subTitle;

        return $this;
    }

    public function getImage(): ?string
    {
        return $this->image;
    }

    public function setImage(string $image): self
    {
        $this->image = $image;

        return $this;
    }

    public function getCreatedAt(): ?\DateTimeInterface
    {
        return $this->created_at;
    }

    public function setCreatedAt(\DateTimeInterface $created_at): self
    {
        $this->created_at = $created_at;

        return $this;
    }

    public function getLink(): ?string
    {
        return $this->link;
    }

    public function setLink(?string $link): self
    {
        $this->link = $link;

        return $this;
    }

    public function getUpdatedAt(): ?\DateTimeInterface
    {
        return $this->updated_at;
    }

    public function setUpdatedAt(\DateTimeInterface $updated_at): self
    {
        $this->updated_at = $updated_at;

        return $this;
    }
}

le fichier conf de Vich :

vich_uploader:
    db_driver: orm

    mappings:
        works_image:
            uri_prefix: /images/works
            upload_destination: '%kernel.project_dir%/public/images/works'
            namer: Vich\UploaderBundle\Naming\UniqidNamer

Merci