Why no indented ifs?

gistfile1.php

/**
     * {@inheritdoc}
     * 
     * @note Image dimensions returned as array(width, height)
     */
    public function fetchMetaDataFrom($filePath)
    {
        if (file_exists($filePath))
        {
            if ($metadata = @getimagesize($filePath) !== false)
            {
                list($width, $height, $type, /** Skip $attr **/) = $metadata;

                $extension = $this->resolveImageType($type);

                if (in_array($extension, $this->allowedImageTypes))
                {
                    return array($width, $height);
                }
                else
                {
                    throw new MetaDataImageExtensionNotAllowedException(sprintf("File %s wasn't in allowed image types: %s", $extension, print_r($this->allowedImageTypes, true)));
                }
            }
            else
            {
                throw new MetaDataFileNotReadableException(sprintf("File %s metadata couldn't be read. Permissions problem?", $filePath));
            }
        }
        else
        {
            throw new MetaDataFileNotFoundException(sprintf("File %s could not be found for metadata retrieval", $filePath));
        }
    }

<?php
public function fetchMetaDataFrom($filepath)
{
    if (!file_exists($filepath)) {
        throw new MetaDataFileNotFoundException;
    }

    list($width, $height, /** Skip $attr **/) = $this->getImageMeta($filepath);

    return array($width, $height);
}

private function getImageMeta($filepath) {
    $metadata = @getimagesize($filePath);
    if ($metadata === FALSE) {
        throw new MetaDataFileNotReadableException;
    }

    $type = $metadata[2];
    // I would validate the extension here
    $this->validateImageType($type);

    return $metadata;
}