Auto Resize Images instead of Original in Wordpress

function replace_uploaded_image($image_data) { // if there is no large image : return if (!isset($image_data['sizes']['large'])) return $image_data; // paths to the uploaded image and the large image $upload_dir = wp_upload_dir(); $uploaded_image_location = $upload_dir['basedir'] . '/' .$image_data['file']; $large_image_location = $upload_dir['path'] . '/'.$image_data['sizes']['large']['file']; // delete the uploaded image unlink($uploaded_image_location); // rename the large image rename($large_image_location,$uploaded_image_location); // update image metadata and return them $image_data['width'] = $image_data['sizes']['large']['width']; $image_data['height'] = $image_data['sizes']['large']['height']; unset($image_data['sizes']['large']); return $image_data; } add_filter('wp_generate_attachment_metadata','replace_uploaded_image');