How to upload an image in yii2?

Question

Yii

Hello. There is a test. When creating a question, the administrator needs to be able to upload an image to the question, and the user can see it all
Form

<?php

use yii\helpers\ArrayHelper;
use yii\helpers\Html;
use yii\widgets\ActiveForm;

/* @var $this yii\web\View */
/* @var $model common\models\Question */
/* @var $form yii\widgets\ActiveForm */
?>

<div class="question-form">
   
    <?php $form = ActiveForm::begin(); ?>

    <?= $form->field($model, 'text')->textInput(['maxlength' => true]) ?>
    
 

    <?php if ($model->isNewRecord)  echo Html::activeDropDownList($model, 'test_id',
        ArrayHelper::map(\common\models\Test::find()->all(), 'id', 'name'), ['class' => 'form-control']) ?>

    <br>
      <div class="form-group">
        <?= Html::submitButton($model->isNewRecord ? 'Создать' : 'Обновить', ['class' => $model->isNewRecord ? 'btn btn-success' : 'btn btn-primary']) ?>
    </div>

    <?php ActiveForm::end(); ?>

</div>

Controller

<?php

namespace backend\controllers;

use common\models\Test;
use common\models\TestQuestion;
use Yii;
use common\models\Question;
use common\models\QuestionSearch;
use yii\web\Controller;
use yii\web\NotFoundHttpException;
use yii\filters\VerbFilter;

/**
 * QuestionController implements the CRUD actions for Question model.
 */
class QuestionController extends Controller
{
    /**
     * @inheritdoc
     */
    public function behaviors()
    {
        return [
            'verbs' => [
                'class' => VerbFilter::className(),
                'actions' => [
                    'delete' => ['POST'],
                ],
            ],
        ];
    }

    /**
     * Lists all Question models.
     * @return mixed
     */
    public function actionIndex()
    {
        $searchModel = new QuestionSearch();
        $dataProvider = $searchModel->search(Yii::$app->request->queryParams);
        return $this->render('index', [
            'searchModel' => $searchModel,
            'dataProvider' => $dataProvider,
        ]);
    }

    /**
     * Displays a single Question model.
     * @param integer $id
     * @return mixed
     */
    public function actionView($id)
    {
        return $this->render('view', [
            'model' => $this->findModel($id),
        ]);
    }

    /**
     * Creates a new Question model.
     * If creation is successful, the browser will be redirected to the 'view' page.
     * @return mixed
     */
    public function actionCreate()
    {
        $model = new Question();
        $post = Yii::$app->request->post();
        if ($model->load($post) && $model->save()) {
            $test_question_model = new TestQuestion();
            $test_question_model->test_id = $post['Question']['test_id'];
            $test_question_model->question_id = $model->id;
            $test_question_model->save();
            
    
            return $this->redirect(['view', 'id' => $model->id]);
        } else {
            return $this->render('create', [
                'model' => $model,
            ]);
        }
    }
    

    /**
     * Updates an existing Question model.
     * If update is successful, the browser will be redirected to the 'view' page.
     * @param integer $id
     * @return mixed
     */
    public function actionUpdate($id)
    {
        $model = $this->findModel($id);

        if ($model->load(Yii::$app->request->post()) && $model->save()) {
            return $this->redirect(['view', 'id' => $model->id]);
        } else {
            return $this->render('update', [
                'model' => $model,
            ]);
        }
    }

    /**
     * Deletes an existing Question model.
     * If deletion is successful, the browser will be redirected to the 'index' page.
     * @param integer $id
     * @return mixed
     */
    public function actionDelete($id)
    {
        $this->findModel($id)->delete();

        return $this->redirect(['index']);
    }

    /**
     * Finds the Question model based on its primary key value.
     * If the model is not found, a 404 HTTP exception will be thrown.
     * @param integer $id
     * @return Question the loaded model
     * @throws NotFoundHttpException if the model cannot be found
     */
    protected function findModel($id)
    {
        if (($model = Question::findOne($id)) !== null) {
            return $model;
        } else {
            throw new NotFoundHttpException('The requested page does not exist.');
        }
    }
}