diff --git a/include/image-commands.mk b/include/image-commands.mk
index 9281b91990..8ed705a7f4 100644
--- a/include/image-commands.mk
+++ b/include/image-commands.mk
@@ -269,8 +269,10 @@ define Build/xor-image
 endef
 
 define Build/check-size
-	@[ $$(($(subst k,* 1024,$(subst m, * 1024k,$(if $(1),$(1),$(IMAGE_SIZE)))))) -ge "$$(stat -c%s $@)" ] || { \
-		echo "WARNING: Image file $@ is too big" >&2; \
+	@imagesize="$$(stat -c%s $@)"; \
+	limitsize="$$(($(subst k,* 1024,$(subst m, * 1024k,$(if $(1),$(1),$(IMAGE_SIZE))))))"; \
+	[ $$limitsize -ge $$imagesize ] || { \
+		echo "WARNING: Image file $@ is too big: $$imagesize > $$limitsize" >&2; \
 		rm -f $@; \
 	}
 endef