Index: typo3/sysext/cms/tslib/class.tslib_content.php
===================================================================
--- typo3/sysext/cms/tslib/class.tslib_content.php	(revision 6485)
+++ typo3/sysext/cms/tslib/class.tslib_content.php	(working copy)
@@ -5343,7 +5343,11 @@
 							$gifCreator->init();
 
 							if ($GLOBALS['TSFE']->config['config']['meaningfulTempFilePrefix'])	{
-								$gifCreator->filenamePrefix = $GLOBALS['TSFE']->fileNameASCIIPrefix(preg_replace('/\.[[:alnum:]]+$/','',basename($theImage)),intval($GLOBALS['TSFE']->config['config']['meaningfulTempFilePrefix']),'_');
+								$filename = basename($theImage);
+									// remove extension
+								$filename = substr($filename, 0, strrpos($filename, '.'));
+								$gifCreator->filenamePrefix = substr($filename, 0, intval($GLOBALS['TSFE']->config['config']['meaningfulTempFilePrefix']));
+								unset($filename);
 							}
 
 							if ($fileArray['sample'])	{