Resolved: Joi requiring fields when it shoudnt be

module.exports.postsValidation = (data) => {
  const schema = Joi.object({
    textfield: Joi.string().max(280),
    picture: Joi.string(),
  });

  return schema.validate(data);
};

router.post("/create", authenticateToken, async (req, res) => {
  try {
    if ((req.body.textfield == "") & (req.body.picture == "")) {
      return res.status(400).json("Fill one of the fields");
    }

    const { error } = postsValidation(req.body);
    if (error) return res.status(400).json(error.details[0].message);

    // Getting info for new post
    const newPost = new Post({
      textfield: req.body.textfield,
      picture: req.body.picture,
      ownerId: req.user._id,
    });

    // Saving new post
    await newPost.save();

    res.json(newPost);
  } catch (error) {
    res.sendStatus(500);
  }
});

[Error [ValidationError]: "picture" is not allowed to be empty] {
  _original: { textfield: 'sssss', picture: '' },
  details: [
    {
      message: '"picture" is not allowed to be empty',
      path: [Array],
      type: 'string.empty',
      context: [Object]
    }
  ]
}