core-bundle/src/Resources/contao/library/Contao/Folder.php
protected function getSize()
	{
		$intSize = 0;

		foreach (scan($this->strRootDir . '/' . $this->strFolder, true) as $strFile)
		{
			if (strncmp($strFile, '.', 1) === 0)
			{
				continue;
			}

			if (is_dir($this->strRootDir . '/' . $this->strFolder . '/' . $strFile))
			{
				$objFolder = new self($this->strFolder . '/' . $strFile);
				$intSize += $objFolder->size;
			}
			else
			{
				$objFile = new File($this->strFolder . '/' . $strFile);
				$intSize += $objFile->size;
			}
		}

		return $intSize;
	}
protected function getSize()
	{
		$intSize = 0;

		foreach (scan($this->strRootDir . '/' . $this->strFolder, true) as $strFile)
		{
			if (strncmp($strFile, '.', 1) === 0)
			{
				continue;
			}

			if (is_dir($this->strRootDir . '/' . $this->strFolder . '/' . $strFile))
			{
				$objFolder = new self($this->strFolder . '/' . $strFile);
				$intSize += $objFolder->size;
			}
			else
			{
				$objFile = new File($this->strFolder . '/' . $strFile);
				$intSize += $objFile->size;
			}
		}

		return $intSize;
	}
Return the size of the folder

@return integer The folder size in bytes