{namespace i=TYPO3\CMS\Install\ViewHelpers}
This verifies that ImageMagick is able to write GIF and PNG files. The GIF-file is attempted compressed with LZW by the \TYPO3\CMS\Core\Imaging\GraphicalFunctions::gifCompress() function.
\TYPO3\CMS\Core\Imaging\GraphicalFunctions::gifCompress()
Test-Image by Rotkaeppchen68 (in de.wikipedia) [GFDL or CC-BY-SA-3.0], via Wikimedia Commons