docs: 重写 README 界面预览,换新 UI 的 1920×1080 截图

- hero 图换成新首页;预览网格改为画图台/概览/模型/渠道/用户/日志六张
- 删除账号池时代的 accounts.png,新增 channels.png、users.png
- 去掉"深/浅双主题"描述(现为固定浅色),用户端补"无限画布"
- README.en.md 补上此前缺失的截图区,与中文版对齐

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

README.en.md

@@ -20,10 +20,43 @@
 
 [Live Demo](https://vividai.run) · [Features](#-features) · [Deploy](#-deployment) · [API](#-vivid-protocol-api)
 
+<br/>
+
+<img src="docs/screenshots/home.png" alt="image2api — landing" width="860" />
+
 </div>
 
 ---
 
+## 🖼️ Screenshots
+
+<div align="center">
+<sub>✨ Vivid-style light UI · channel routing · data-driven ops dashboard</sub>
+</div>
+
+<table>
+  <tr>
+    <td width="33%"><img src="docs/screenshots/playground.png" alt="Studio" /></td>
+    <td width="33%"><img src="docs/screenshots/dashboard.png" alt="Dashboard" /></td>
+    <td width="33%"><img src="docs/screenshots/models.png" alt="Models" /></td>
+  </tr>
+  <tr>
+    <td align="center"><b>🎨 Studio</b><br/><sub>image + video · reference uploads · live pricing</sub></td>
+    <td align="center"><b>📊 Dashboard</b><br/><sub>users / volume / channel health / 24h trend</sub></td>
+    <td align="center"><b>🧩 Models</b><br/><sub>channel bindings + weights · standard + reseller pricing</sub></td>
+  </tr>
+  <tr>
+    <td width="33%"><img src="docs/screenshots/channels.png" alt="Channels" /></td>
+    <td width="33%"><img src="docs/screenshots/users.png" alt="Users" /></td>
+    <td width="33%"><img src="docs/screenshots/logs.png" alt="Logs" /></td>
+  </tr>
+  <tr>
+    <td align="center"><b>🔌 Channels</b><br/><sub>save-to-sync upstream models · live balance · failover</sub></td>
+    <td align="center"><b>👥 Users</b><br/><sub>roles / concurrency groups / credits · batch ops</sub></td>
+    <td align="center"><b>📜 Logs</b><br/><sub>success / failed / running · prompts and latency kept</sub></td>
+  </tr>
+</table>
+
 ## ✨ Introduction
 
 **image2api** is a homogeneous gateway. Upstream, it connects any number of **vivid-protocol (vividai) instances** as "channels" and routes jobs across them. Downstream, it exposes the same **vivid-protocol API** to callers: `POST /v1/generate` (NDJSON stream) · `POST /v1/uploads` (presigned upload) · `GET /v1/models` · `GET /v1/balance`. No built-in provider code, no account pools — an upstream is just another vividai instance, so gateways can be layered arbitrarily.