diff --git a/benchmarks/img/bench.py b/benchmarks/img/bench.py
index 3df643c..f12fc15 100644
--- a/benchmarks/img/bench.py
+++ b/benchmarks/img/bench.py
@@ -48,11 +48,14 @@ def grouped(iterable, n):
 total_initial_size = sum(pre_size_list)
 total_final_size = sum(post_size_list)
 delta = total_initial_size - total_final_size
+total_percent = (total_final_size / total_initial_size) * 100
 
+print(f"Total files: {len(percent_list)}")
 print(f"\nInitial:\t{total_initial_size:>8} B")
 print(f"Final:  \t{total_final_size:>8} B")
-print(f"Delta: -{delta} B")
-print(f"Mean: {mean:.2f}%")
+print(f"\nDelta: -{delta} B")
+print(f"Total: {total_percent:.2f}% of initial size")
+print(f"Mean image reduction: {mean:.2f}%")
 try:
     import numpy as np
 
diff --git a/setup.cfg b/setup.cfg
new file mode 100644
index 0000000..43d7a3a
--- /dev/null
+++ b/setup.cfg
@@ -0,0 +1,2 @@
+[flake8]
+max-line-length = 90
diff --git a/src/crunch.py b/src/crunch.py
index 6282dde..45c2700 100755
--- a/src/crunch.py
+++ b/src/crunch.py
@@ -148,11 +148,7 @@ def main(argv):
         # PNG validity test
         if not is_valid_png(png_path):
             sys.stderr.write(
-                ERROR_STRING
-                + " '"
-                + png_path
-                + "' is not a valid PNG file."
-                + os.linesep
+                ERROR_STRING + " '" + png_path + "' is not a valid PNG file." + os.linesep
             )
             if is_gui(argv):
                 log_error(png_path + " is not a valid PNG file.")
@@ -180,9 +176,7 @@ def main(argv):
             + os.linesep
         )
         if is_gui(argv):
-            log_error(
-                "pngquant was not found on the expected path " + PNGQUANT_EXE_PATH
-            )
+            log_error("pngquant was not found on the expected path " + PNGQUANT_EXE_PATH)
         sys.exit(1)
     elif not os.path.exists(ZOPFLIPNG_EXE_PATH):
         sys.stderr.write(
@@ -239,6 +233,9 @@ def main(argv):
             if is_gui(argv):
                 log_error(str(e))
             sys.exit(1)
+        finally:
+            p.close()
+            p.join()
 
     # end of successful processing, exit code 0
     if is_gui(argv):
@@ -272,9 +269,7 @@ def optimize_png(png_path):
     pngquant_options = (
         " --quality=80-98 --skip-if-larger --force --strip --speed 1 --ext -crunch.png "
     )
-    pngquant_command = (
-        PNGQUANT_EXE_PATH + pngquant_options + shellquote(img.pre_filepath)
-    )
+    pngquant_command = PNGQUANT_EXE_PATH + pngquant_options + shellquote(img.pre_filepath)
     try:
         subprocess.check_output(pngquant_command, stderr=subprocess.STDOUT, shell=True)
     except CalledProcessError as cpe:
diff --git a/src/install-dependencies.sh b/src/install-dependencies.sh
index ba10eda..c6f7fd0 100755
--- a/src/install-dependencies.sh
+++ b/src/install-dependencies.sh
@@ -15,8 +15,8 @@ PNGQUANT_EXE="$PNGQUANT_BUILD_DIR/pngquant"
 ZOPFLIPNG_BUILD_DIR="$HOME/zopfli"
 ZOPFLIPNG_EXE="$ZOPFLIPNG_BUILD_DIR/zopflipng"
 
-PNGQUANT_VERSION_TAG="2.12.5"
-ZOPFLIPNG_VERSION_TAG="v2.2.0"
+PNGQUANT_VERSION_TAG="2.13.0"
+ZOPFLIPNG_VERSION_TAG="v2.3.0"
 LIBPNG_VERSION="1.6.37"
 LIBPNG_VERSION_FILE="v$LIBPNG_VERSION.tar.gz"