diff --git a/.vscode/settings.json b/.vscode/settings.json
index 746b6f83..c0e7979d 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -47,6 +47,9 @@
     "[html]": {
         "editor.formatOnSave": false,
     },
+    "files.associations": {
+        "*.makefile": "makefile"
+    },
     "editor.codeActionsOnSaveTimeout": 9001,
     "editor.formatOnSaveTimeout": 9001,
     //
diff --git a/scripts/deps-docker/Dockerfile b/scripts/deps-docker/Dockerfile
index d91c4971..b9db1b38 100644
--- a/scripts/deps-docker/Dockerfile
+++ b/scripts/deps-docker/Dockerfile
@@ -40,13 +40,10 @@ RUN     cd ogvjs-$ver_ogvjs \
             ogv-decoder-audio-vorbis-wasm.js \
             ogv-decoder-audio-vorbis-wasm.wasm \
             dynamicaudio.swf \
-            /z/dist \
+            /z/dist
+
 # compress
-        && find /z/dist | \
-        while IFS= read -r x; do \
-            echo "compressing $x"; \
-            pigz -11 -I 50 $x; \
-        done
-        # -I 1000 = 503587
-        # -I 15   = 503650 (default)
-        # -I 3    = 503994
+COPY    zopfli.makefile /z/dist/Makefile
+RUN     cd /z/dist \
+        && make -j$(nproc) \
+        && rm Makefile
diff --git a/scripts/deps-docker/Makefile b/scripts/deps-docker/Makefile
index ccbb44b6..6e919fda 100644
--- a/scripts/deps-docker/Makefile
+++ b/scripts/deps-docker/Makefile
@@ -16,6 +16,11 @@ all:
 
 	chown -R `stat $(self) -c %u:%g` $(vend)
 
+purge:
+	-docker kill `docker ps -q`
+	-docker rm   `docker ps -qa`
+	-docker rmi  `docker images -qa`
+
 sh:
 	@printf "\n\033[1;31mopening a shell in the most recently created docker image\033[0m\n"
 	docker run --rm -it `docker images -aq | head -n 1` /bin/bash
diff --git a/scripts/deps-docker/zopfli.makefile b/scripts/deps-docker/zopfli.makefile
new file mode 100644
index 00000000..2934ae62
--- /dev/null
+++ b/scripts/deps-docker/zopfli.makefile
@@ -0,0 +1,6 @@
+all: $(addsuffix .gz, $(wildcard *.*))
+
+%.gz: %
+	pigz -11 -J 34 -I 573 $<
+
+# pigz -11 -J 34 -I 100 -F < $< > $@.first