update img url

Author: UlricQin

README.md

@@ -54,35 +54,35 @@
 
 你可以在页面的右上角，切换语言和主题，目前我们支持英语、简体中文、繁体中文。
 
-![语言切换](https://download.flashcat.cloud/ulric/n9e-switch-i18n.png)
+![语言切换](doc/img/readme/n9e-switch-i18n.png)
 
 即时查询，类似 Prometheus 内置的查询分析页面，做 ad-hoc 查询，夜莺做了一些 UI 优化，同时提供了一些内置 promql 指标，让不太了解 promql 的用户也可以快速查询。
 
-![即时查询](https://download.flashcat.cloud/ulric/20240513103305.png)
+![即时查询](doc/img/readme/20240513103305.png)
 
 当然，也可以直接通过指标视图查看，有了指标视图，即时查询基本可以不用了，或者只有高端玩家使用即时查询，普通用户直接通过指标视图查询即可。
 
-![指标视图](https://download.flashcat.cloud/ulric/20240513103530.png)
+![指标视图](doc/img/readme/20240513103530.png)
 
 夜莺内置了常用仪表盘，可以直接导入使用。也可以导入 Grafana 仪表盘，不过只能兼容 Grafana 基本图表，如果已经习惯了 Grafana 建议继续使用 Grafana 看图，把夜莺作为一个告警引擎使用。
 
-![内置仪表盘](https://download.flashcat.cloud/ulric/20240513103628.png)
+![内置仪表盘](doc/img/readme/20240513103628.png)
 
 除了内置的仪表盘，也内置了很多告警规则，开箱即用。
 
-![内置告警规则](https://download.flashcat.cloud/ulric/20240513103825.png)
+![内置告警规则](doc/img/readme/20240513103825.png)
 
 
 
 ## 产品架构
 
 社区使用夜莺最多的场景就是使用夜莺做告警引擎，对接多套时序库，统一告警规则管理。绘图仍然使用 Grafana 居多。作为一个告警引擎，夜莺的产品架构如下：
 
-![产品架构](https://download.flashcat.cloud/ulric/20240221152601.png)
+![产品架构](doc/img/readme/20240221152601.png)
 
 对于个别边缘机房，如果和中心夜莺服务端网络链路不好，希望提升告警可用性，我们也提供边缘机房告警引擎下沉部署模式，这个模式下，即便网络割裂，告警功能也不受影响。
 
-![边缘部署模式](https://download.flashcat.cloud/ulric/20240222102119.png)
+![边缘部署模式](doc/img/readme/20240222102119.png)
 
 
 ## 交流渠道

README_en.md

@@ -53,43 +53,43 @@ Originally developed and open-sourced by Didi, Nightingale was donated to the Ch
 
 You can switch languages and themes in the top right corner. We now support English, Simplified Chinese, and Traditional Chinese. 
 
-![18n switch](https://download.flashcat.cloud/ulric/n9e-switch-i18n.png)
+![18n switch](doc/img/readme/n9e-switch-i18n.png)
 
 ### Instant Query
 
 Similar to the built-in query analysis page in Prometheus, Nightingale offers an ad-hoc query feature with UI enhancements. It also provides built-in PromQL metrics, allowing users unfamiliar with PromQL to quickly perform queries.
 
-![Instant Query](https://download.flashcat.cloud/ulric/20240513103305.png)
+![Instant Query](doc/img/readme/20240513103305.png)
 
 ### Metric View
 
 Alternatively, you can use the Metric View to access data. With this feature, Instant Query becomes less necessary, as it caters more to advanced users. Regular users can easily perform queries using the Metric View.
 
-![Metric View](https://download.flashcat.cloud/ulric/20240513103530.png)
+![Metric View](doc/img/readme/20240513103530.png)
 
 ### Built-in Dashboards
 
 Nightingale includes commonly used dashboards that can be imported and used directly. You can also import Grafana dashboards, although compatibility is limited to basic Grafana charts. If you’re accustomed to Grafana, it’s recommended to continue using it for visualization, with Nightingale serving as an alerting engine.
 
-![Built-in Dashboards](https://download.flashcat.cloud/ulric/20240513103628.png)
+![Built-in Dashboards](doc/img/readme/20240513103628.png)
 
 ### Built-in Alert Rules
 
 In addition to the built-in dashboards, Nightingale also comes with numerous alert rules that are ready to use out of the box.
 
-![Built-in Alert Rules](https://download.flashcat.cloud/ulric/20240513103825.png)
+![Built-in Alert Rules](doc/img/readme/20240513103825.png)
 
 
 
 ## Architecture
 
 In most community scenarios, Nightingale is primarily used as an alert engine, integrating with multiple time-series databases to unify alert rule management. Grafana remains the preferred tool for visualization. As an alert engine, the product architecture of Nightingale is as follows:
 
-![Product Architecture](https://download.flashcat.cloud/ulric/20240221152601.png)
+![Product Architecture](doc/img/readme/20240221152601.png)
 
 For certain edge data centers with poor network connectivity to the central Nightingale server, we offer a distributed deployment mode for the alert engine. In this mode, even if the network is disconnected, the alerting functionality remains unaffected.
 
-![Edge Deployment Mode](https://download.flashcat.cloud/ulric/20240222102119.png)
+![Edge Deployment Mode](doc/img/readme/20240222102119.png)
 
 
 ## Communication Channels