diff --git a/docs/changes.md b/docs/changes.md
index f52ad29bd..166bcb93e 100644
--- a/docs/changes.md
+++ b/docs/changes.md
@@ -1,4 +1,8 @@
 # 最新动态
+* 2018/11/14
+  * 完善digit\_clock
+  * change  WITH\_NANOVG\_GL to WITH\_NANOVG\_GPU
+
 * 2018/11/13
   * 修改agg/agge为nanovg后端时linecap的BUG。
 
diff --git a/docs/faq.md b/docs/faq.md
index 89d5bdf41..c46469bb3 100644
--- a/docs/faq.md
+++ b/docs/faq.md
@@ -48,7 +48,7 @@
 
 可以用imagemagic转换：
 ```
-convert test.png +dither test.jpg
+convert bg.png  -ordered-dither o8x8,32,64,32 bg.jpg
 ```
 > 参考：http://www.imagemagick.org/Usage/quantize/