Are ZIP files and PHP the best way to transfer bulk data?

MIT App Inventor Help
1

Moving uncompressed bulk data loads between client(APP) and server is not really realistic or optimal. Selecting multiple BLOB images from a MySQL database that is. How can I ZIP the server folder of images and un-ZIP it in the APP ?

2

This php zip image files

<?php
$dir = 'uploads/';
$zipFileName = 'comprimido.zip';
$zip = new ZipArchive();

if ($zip->open($zipFileName, ZipArchive::CREATE | ZipArchive::OVERWRITE) === true) {
    $files = scandir($dir);
    foreach ($files as $file) {
        if ($file !== '.' && $file !== '..' && !is_dir($file)) {
            $extension = pathinfo($file, PATHINFO_EXTENSION);
            if (in_array($extension, array('jpg', 'jpeg', 'png', 'gif'))) {
                $filePath = $dir . $file;
                $zip->addFile($filePath, $file);
            }
        }
    }
    $zip->close();

    echo "Compress";
} else {
    echo "Error.";
}
?>