diff --git a/tests/build-in-docker.sh b/tests/build-in-docker.sh
index 63e5dea..b3d9a96 100755
--- a/tests/build-in-docker.sh
+++ b/tests/build-in-docker.sh
@@ -11,3 +11,4 @@ docker cp $PWD/build_in_docker/pico_hsm temp_container:/pico_hsm
 docker commit temp_container pico-hsm-test:bullseye
 docker stop temp_container
 docker rm temp_container
+docker image prune -f