update doc

Author: alexcheng1982

README.md

@@ -3,9 +3,9 @@
 [![build](https://github.com/JavaAIDev/chat-agent-ui/actions/workflows/build.yml/badge.svg)](https://github.com/JavaAIDev/chat-agent-ui/actions/workflows/build.yml)
 ![Maven Central Version](https://img.shields.io/maven-central/v/com.javaaidev.chatagentui/chat-agent-ui-parent)
 
-A simple UI to test conversational agents. It's built
-using [assistant-ui](https://www.assistant-ui.com/) with
-a [LocalRuntime](https://www.assistant-ui.com/docs/runtimes/custom/local).
+A simple UI to test conversational agents. It's built using [assistant-ui](https://www.assistant-ui.com/) with a [LocalRuntime](https://www.assistant-ui.com/docs/runtimes/custom/local).
+
+## Usage
 
 The API must be available at `/chat`.
 
@@ -19,4 +19,12 @@ Features:
 - Reasoning output from LLMs
 - Attachments: images and text files
 
-![Chat agent UI](./chat-agent-ui.png)
+## Screenshots
+
+### Text and Reasoning
+
+![Text and Reasoning](./chat-agent-ui.png)
+
+### Attachment
+
+![Attachment](./chat-agent-ui-attachment.png)