HTML表单里面如果需要上传文件，那么对应的PHP处理上传的代码如下 ：

<?php
if(isset($_FILES['image'])){
    $errors= array();
    $file_name = $_FILES['image']['name'];
    $file_size =$_FILES['image']['size'];
    $file_tmp =$_FILES['image']['tmp_name'];
    $file_type=$_FILES['image']['type'];
    $file_ext=strtolower(end(explode('.',$_FILES['image']['name'])));
    
    $extensions= array("jpeg","jpg","png");
    
    if(in_array($file_ext,$extensions)=== false){
       $errors[]="extension not allowed, please choose a JPEG or PNG file.";
    }
    
    if($file_size > 2097152){
       $errors[]='File size must be excately 2 MB';
    }
    
    if(empty($errors)==true){
       move_uploaded_file($file_tmp,"images/".$file_name);
       echo "Success";
    }else{
       print_r($errors);
    }
 }

如果上传的文件比较大，php.ini 需要配置upload_max_filesize和post_max_size。