[Doc] update diffusion_acceleration.md & FAQ memory troubleshooting (#406)

Signed-off-by: David Chen <530634352@qq.com>

docs/getting_started/quickstart.md

@@ -40,4 +40,27 @@ For more usages, please refer to [offline inference](../user_guide/examples/offl
 
 ## Online Serving with OpenAI-Completions API
 
-Please refer to [online serving](../user_guide/examples/online_serving/qwen2_5_omni.md)
+Text-to-image generation quickstart with vLLM-Omni:
+
+```bash
+vllm serve Tongyi-MAI/Z-Image-Turbo --omni --port 8091
+```
+
+```bash
+curl -s http://localhost:8091/v1/chat/completions \
+  -H "Content-Type: application/json" \
+  -d '{
+    "messages": [
+      {"role": "user", "content": "a cup of coffee on the table"}
+    ],
+    "extra_body": {
+      "height": 1024,
+      "width": 1024,
+      "num_inference_steps": 50,
+      "guidance_scale": 4.0,
+      "seed": 42
+    }
+  }' | jq -r '.choices[0].message.content[0].image_url.url' | cut -d',' -f2 | base64 -d > coffee.png
+```
+
+For more details, please refer to [online serving](../user_guide/examples/online_serving/text_to_image.md).