Parse Images for Colors and Populate a CSS File. Uses composer library ColorExtractor

composer.json

{
    "name": "artlung/parse-images-for-color",
    "autoload": {
        "psr-4": {
            "Artlung\\ParseImagesForColor\\": "src/"
        }
    },
    "authors": [
        {
            "name": "Joe Crawford",
            "email": "joe@artlung.com"
        }
    ],
    "require": {
        "league/color-extractor": "^0.4.0"
    }
}

parseImagesForCSSColors.php

<?php
require 'vendor/autoload.php';
// https://stackoverflow.com/questions/10290259/detect-main-colors-in-an-image-with-php
use League\ColorExtractor\Color;
use League\ColorExtractor\ColorExtractor;
use League\ColorExtractor\Palette;

$directory = '../thumbs-trimmed/shot-scraper';
$files = scandir($directory);
$files = array_diff($files, array('..', '.'));
$files = array_values($files);
$fileName = 'output.css';

foreach ($files as $file) {
    if (strpos($file, '.png') === false) {
        continue;
    }
    ob_start();
    $className = '.' . str_replace('.png',
            '', str_replace('artlung-com-headers--',
                'header-', $file));
    print 'body' . $className . " {\n";
    $im = imagecreatefrompng($directory . '/' . $file);
    if (!$im) {
        echo '/* Could not create image resource for ' . $file . " */\n";
        continue;
    }
    $palette = Palette::fromGD($im);
    $topColors = $palette->getMostUsedColors(12);
    $colorCount = count($palette);
    // an extractor is built from a palette
    $extractor = new ColorExtractor($palette);
    // League\ColorExtractor\ColorExtractor library does work to
    // get the most representative colors
    $colors = $extractor->extract(5);
    // populate the css file with colors
    foreach($colors as $color) {
        printf("--color: %s;\n", Color::fromIntToHex($color));
        printf("--backgroundColor: %s;\n", Color::fromIntToHex($color));
    }
    print "}\n";
    $css = ob_get_clean();
    file_put_contents($fileName, $css, FILE_APPEND);
}