为什么React在src上说无效的prop？

Question

我不确定为什么吗？，我用谷歌搜索了几次，什么都没有出现...

<img src={this.props.user.picture || this.props.user.gravatar} />
 {' '}{this.props.user.name || this.props.user.email || this.props.user.id}{' '}

更新： 抱歉，应该早于此

Gravatar的辅助方法

userSchema.methods.gravatar = function(size) {
  console.log(gravatar);
  if (!size) {
    size = 200;
  }
  if (!this.email) {
    return `https://gravatar.com/avatar/?s=${size}&d=retro`;
  }
  const md5 = crypto.createHash('md5').update(this.email).digest('hex');
  return `https://gravatar.com/avatar/${md5}?s=${size}&d=retro`;
};

和猫鼬的用户模型：

var userSchema = new mongoose.Schema({
  name: String,
  email: { type: String, unique: true, lowercase: true},      password: String,
  passwordResetToken: String,
  passwordResetExpires: Date,
  gender: String,
  location: String,
  website: String,
  picture: String,
...