diff --git a/Dockerfile b/Dockerfile
index 315f13e..7127552 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -7,3 +7,7 @@ RUN apt-get update && \
     python3-pygments python3-geopandas \
     latexmk make \
     docker.io
+
+COPY layer2img.py /tmp/layer2img.py
+RUN python3 /tmp/layer2img.py -o /tmp/foo.pdf
+RUN rm /tmp/layer2img.py
diff --git a/in-container b/in-container
index 93632e2..fb8eabd 100755
--- a/in-container
+++ b/in-container
@@ -12,7 +12,7 @@ set -euo pipefail
 
 NAME=wm-mj-build
 if [[ -z "$(docker images -q --filter "reference=$NAME")" ]]; then
-    docker build -t "$NAME" - < Dockerfile
+    docker build -t "$NAME" .
 fi
 
 exec docker run -ti --rm \