Drupal 8: Get Image URL / URI with Image Style

get_image_path_with_image_style.php

<?php
use Drupal\file\Entity\File;
use Drupal\image\Entity\ImageStyle;
// File ID.
$fid = 123;
// Load file.
$file = File::load($fid);
// Get origin image URI.
$image_uri = $file->getFileUri();
// Load image style "thumbnail".
$style = ImageStyle::load('thumbnail');
// Get URI.
$uri = $style->buildUri($image_uri);
// Get URL.
$url = $style->buildUrl($image_uri);

cool!