Not a valid PNG file - php

Question

I have a code:
<?php
$size = 2000000;
$types = array('image/png', 'image/jpeg');
if(isset($_POST['go'])){
$newName = $id . '.' . $type;
$directory = 'img/avatars/'; //path to folder with images
$picture = $directory . basename($newName);
if (!in_array($_FILES['picture']['type'], $types)) {
die('Wrong type of file. Try another');
} elseif ($_FILES['picture']['size'] > $size) {
die('File is too big. Try another');
} elseif (move_uploaded_file($_FILES['picture']['tmp_name'], $picture)) {
echo "Image was downloaded!";
}
$new_width = 66; //necessary width
$size = getimagesize($picture);
$width = $size[0];
$height = $size[1];
if ($type == 'png') {
$src=ImageCreateFromPng($picture);
}
if ($type == 'jpeg' || $type == 'jpg') {
$src=ImageCreateFromJPEG($picture);
}
$coefficient = $width/$new_width;
$new_height = ceil($height/$coefficient);
$empty_picture = ImageCreateTrueColor($new_width, $new_height);
ImageCopyResampled($empty_picture, $src, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
if ($type == 'png') {
ImagePNG($empty_picture, $picture, -1);
}
if ($type == 'jpeg') {
ImageJPEG($empty_picture, $picture, -1);
}
imagedestroy($src);
}
?>
It returns an error:
imagecreatefrompng(): 'img/avatars/6.png' is not a valid PNG file in
W:\domains\mysite\settings.php
I checked is it png image:
$finfo = finfo_open(FILEINFO_MIME_TYPE);
echo finfo_file($finfo, $picture); // image/png
finfo_close($finfo);
And it returns me: image/png (it is).
So I do not know what is wrong with this code. Would be grateful for any help!