diff --git a/.gitea/workflows/push.yaml b/.gitea/workflows/push.yaml
index 006680e..7f6b235 100644
--- a/.gitea/workflows/push.yaml
+++ b/.gitea/workflows/push.yaml
@@ -28,8 +28,8 @@ jobs:
                   go env -w GOPROXY=https://goproxy.io,direct
                   chown -R root:root /root/.ssh
             - name: Build
-              run: make build
+              run: make force-build
             - name: Check images
-              run: docker ps -a
+              run: docker images
             - name: Push
               run: make push
diff --git a/Makefile b/Makefile
index 0ecc856..dbabbdb 100644
--- a/Makefile
+++ b/Makefile
@@ -1,11 +1,16 @@
-.PHONY: all build push
+.PHONY: all prepare force-build build push
 
 all: build
 
-build:
+prepare:
 	git submodule update --init --remote
 	$(MAKE) -C JOJ3
 	cp JOJ3/build/joj3 bin/
+
+force-build: prepare
+	docker build --no-cache -t focs.ji.sjtu.educn:5000/gitea/runner-images:focs-ubuntu-latest-slim .
+
+build: prepare
 	docker build -t focs.ji.sjtu.edu.cn:5000/gitea/runner-images:focs-ubuntu-latest-slim .
 
 push: