Upload files not loading extension

Question

Hello, I’m trying to generate the filename upado in md5();, but my file extension does not work at the time of upload, follow my class:

<?php

class Upload {

    private $_SupportedFormats = ['image/jpg', 'image/jpeg', 'image/png'];

    private function encryption($str) {
        return md5($str);
    }

    private function verify_file($file) {
        if (is_array($file)) {
            return true;
        } else {
            return false;
        }
    }

    private function verify_format($file) {
        if ($this->verify_file($file)) {
            if (in_array($file['type'], $this->_SupportedFormats)) {
                return true;
            }
        } else {
            return false;
        }
    }

    public function upload_file($file) {
        if ($this->verify_format($file)) {
            move_uploaded_file($file['tmp_name'], FOLDER_UPLOADS . '/' . $this->encryption($file['name']));
            return true;
        } else {
            return false;
        }
    }

}

This is the name of the file being uploaded: d26f85295e5c2da4634ee2bff0c83e1e.

I would like to keep it that way, (with the extension)d26f85295e5c2da4634ee2bff0c83e1e.png.

What’s wrong with my class? I don’t understand if I’m setting $this->encryption($file['name']); Why is the extension disappearing? I’m in over my head.