Index: t3lib/class.t3lib_compressor.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- t3lib/class.t3lib_compressor.php	(revision )
+++ t3lib/class.t3lib_compressor.php	(revision )
@@ -659,7 +659,11 @@
 	protected function retrieveExternalFile($url) {
 		$externalContent = t3lib_div::getUrl($url);
 		$filename = $this->targetDirectory . 'external-' . md5($url);
+
+		//write only if file not exists and md5 of the content is not the same with fetched one
+		if (!file_exists(PATH_site . $filename) && (md5($externalContent) != md5(t3lib_div::getUrl(PATH_site . $filename)))) {
-		t3lib_div::writeFile(PATH_site . $filename, $externalContent);
+			t3lib_div::writeFile(PATH_site . $filename, $externalContent);
+		}
 		return $filename;
 	}
 
\ No newline at end of file