Preserving timestamp when rotating original file

piwigo_thumbgen.sh

@@ -66,8 +66,10 @@ do
 			if [ "$quali" -le "0" ]; then
 				quali=94
 			fi
-			echo "rotate with quality $quali : $file"
-			mogrify -auto-orient -quality ${quali} "${file}" #> /dev/null 2>&1 
+			echo "rotate with quality $quali preserving timestamp: $file"
+            TIMESTAMP="$( ls -l --time-style='+%Y%m%d%H%M.%S' "${file}" | cut  --delimiter=' ' --fields=6 )"
+			mogrify -auto-orient -quality ${quali} "${file}"
+            touch -t ${TIMESTAMP} "${file}"
 		fi
 
                 #echo "MISSING! ${destDir}${fnNoExt}-me.${fnExt}"