diff --git a/merge_images b/merge_images
index 7b8a2d3..3bc2b3d 100755
--- a/merge_images
+++ b/merge_images
@@ -12,7 +12,6 @@ Author: Stephan Porada <sporada@uni-bielefeld.de>
 
 import os
 import argparse
-import subprocess
 
 
 def parse_arguments():
@@ -25,8 +24,10 @@ def parse_arguments():
 
 def merge_images(input_dir, output_dir):
     os.makedirs(output_dir, exist_ok=True)
+    os.makedirs(os.path.join(output_dir, 'testfile.txt'))
     os.system('ls -v {i}/*.* >> {i}file_list.txt'.format(i=input_dir))
-    os.system('convert @{i}/file_list.txt {o}/combined.tiff'.format(i=input_dir, o=output_dir))
+    os.system('convert @{i}/file_list.txt {o}/combined.tiff'.format(i=input_dir,
+                                                                    o=output_dir))
 
 
 def main():