Multiple Image Thumbnails - Command line PHP tool to generate image to represent multiple images

thumb.php

<?php

// By Joe Crawford joe@artlung.com
// September 2023
// intended to be run from the command line
// php thumb.php
// place images in the same directory as this script and their names in the array below
// or place urls in the array below - filenames must be unique

// height and width of the final image, for now the math relies on everything being square
$height = 800;
$width = 800;

$im = imagecreatetruecolor($width, $height);
$color = imagecolorallocate($im, 255, 255, 255);
imagefilledrectangle($im, 0, 0, $width, $height, $color);

$images_to_place_on_base = [
    // place images of urls here or just filenames in the same directory as this script
];

// we output a wide range of possible sizes for the images we place on the base so we can choose one we like
// can be edited but should be smaller than the base image, though it's not precluded that you might want things
// to run off the image
$childImageLengths = [200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 450, 480, 500, 520, 540, 560, 580, 600, 620, 640, 680, 700, 720, 740, 760];

foreach ($childImageLengths as $iterationLength) {
    $childImageWidth = $iterationLength;
    $childImageHeight = $iterationLength;
    // for ($index = 0; $index < count($images_to_place_on_base); $index++) {
    for ($index = count($images_to_place_on_base) -1; $index >= 0; $index--) {
        // if it's the first image, put it in the top left corner
        $x = false;
        $y = false;

        $something_x = intval(($width - $childImageWidth) / (count($images_to_place_on_base) - 1));
        $something_y = intval(($height - $childImageHeight) / (count($images_to_place_on_base) - 1));
        $x = ($width - $childImageWidth) - ($something_x * $index);
        $y = ($height - $childImageHeight) - ($something_y * $index);

        $full_url = $images_to_place_on_base[$index];
        $target_file_name = basename($full_url);

        if (file_exists($target_file_name)) {
//            printf("File %s exists\n", $target_file_name);
        } else {
            printf("File %s does not exist\n", $target_file_name);
            // download it
            $image_data = file_get_contents($full_url);
            file_put_contents($target_file_name, $image_data);
        }

        if ($x !== false && $y !== false) {
            // if jpeg
            if (strpos($target_file_name, '.jpeg') !== false || strpos($target_file_name, '.jpg') !== false) {
                $image = imagecreatefromjpeg($target_file_name);
            }
            // if png
            if (strpos($target_file_name, '.png') !== false) {
                $image = imagecreatefrompng($target_file_name);
            }
            // if gif
            if (strpos($target_file_name, '.gif') !== false) {
                $image = imagecreatefromgif($target_file_name);
            }
            // if webp
            if (strpos($target_file_name, '.webp') !== false) {
                $image = imagecreatefromwebp($target_file_name);
            }
            // if none, exit
            if (!$image) {
                printf("No image for %s\n", $target_file_name);
                exit;
            }

            $image_width = imagesx($image);
            $image_height = imagesy($image);
            $image_width_to_height_ratio = $image_width / $image_height;
            $image_height_to_width_ratio = $image_height / $image_width;
            $image_width = $childImageWidth;
            $image_height = $childImageHeight;
            $image_width = intval($image_width * $image_width_to_height_ratio);
            $image_height = intval($image_height * $image_height_to_width_ratio);
            $image = imagescale($image, $image_width, $image_height);

            printf("Placing image %s at %s,%s\n", $color, $x, $y);

            imagecopy($im, $image, $x, $y, 0, 0, $image_width, $image_height);
        }
    }

//output png to filesystem
    imagepng($im, 'thumbnail_' . $childImageWidth . '.png');
}