how to validate format and size of uploaded file via php

1<?php
2if (isset($_POST["upload"])) {
3    // Get Image Dimension
4    $fileinfo = @getimagesize($_FILES["file-input"]["tmp_name"]);
5    $width = $fileinfo[0];
6    $height = $fileinfo[1];
7    
8    $allowed_image_extension = array(
9        "png",
10        "jpg",
11        "jpeg"
12    );
13    
14    // Get image file extension
15    $file_extension = pathinfo($_FILES["file-input"]["name"], PATHINFO_EXTENSION);
16    
17    // Validate file input to check if is not empty
18    if (! file_exists($_FILES["file-input"]["tmp_name"])) {
19        $response = array(
20            "type" => "error",
21            "message" => "Choose image file to upload."
22        );
23    }    // Validate file input to check if is with valid extension
24    else if (! in_array($file_extension, $allowed_image_extension)) {
25        $response = array(
26            "type" => "error",
27            "message" => "Upload valiid images. Only PNG and JPEG are allowed."
28        );
29        echo $result;
30    }    // Validate image file size
31    else if (($_FILES["file-input"]["size"] > 2000000)) {
32        $response = array(
33            "type" => "error",
34            "message" => "Image size exceeds 2MB"
35        );
36    }    // Validate image file dimension
37    else if ($width > "300" || $height > "200") {
38        $response = array(
39            "type" => "error",
40            "message" => "Image dimension should be within 300X200"
41        );
42    } else {
43        $target = "image/" . basename($_FILES["file-input"]["name"]);
44        if (move_uploaded_file($_FILES["file-input"]["tmp_name"], $target)) {
45            $response = array(
46                "type" => "success",
47                "message" => "Image uploaded successfully."
48            );
49        } else {
50            $response = array(
51                "type" => "error",
52                "message" => "Problem in uploading image files."
53            );
54        }
55    }
56}
57?>
58