update readme

Author: silenceshell

README.md

@@ -5,10 +5,14 @@ top in container.
 Running the original `top` command in a container will not get information of the container, many metrics like uptime, users, load average, tasks, cpu, memory, are about the host in fact. 
 `topic`(**top** **i**n **c**ontainer) will retrieve those metrics from container instead, and shows the status of the container, not the host.
 
-## how to use
+Below shows a container of 1 cpu and 1 Gi running status when stress with `--cpu 2`.
 
-Just download `topic` from GitHub [release page](https://github.com/silenceshell/topic/releases) to the container which you want to inspect, and add `x` attribute to the binary, then run the binary!
+![topic.png](doc/image/topic.png)
 
-## how to build
+## How to use
+
+Download `topic` from GitHub [release page](https://github.com/silenceshell/topic/releases) to the container which you want to inspect, and add `x` attribute to the binary, then run the binary!
+
+## How to build
 
 Run `make build` for linux and amd64. `topic` only support on linux. If you want to run on other architectures, `GOARCH` is need to be set.