Print image size after building it

Makefile

@@ -45,6 +45,8 @@ arch_patch/%: ## apply hardware architecture specific patches to the Dockerfile
 build/%: DARGS?=
 build/%: ## build the latest image for a stack
 	docker build $(DARGS) --rm --force-rm -t $(OWNER)/$(notdir $@):latest ./$(notdir $@)
+	@echo -n "Built image size: "
+	@docker images $(OWNER)/$(notdir $@):latest --format "{{.Size}}"
 
 build-all: $(foreach I,$(ALL_IMAGES),arch_patch/$(I) build/$(I) ) ## build all stacks
 build-test-all: $(foreach I,$(ALL_IMAGES),arch_patch/$(I) build/$(I) test/$(I) ) ## build and test all stacks