image reference image not work

[zhaoyou]

Reference-style image syntax looks like this:

![Alt text][id]
Where “id” is the name of a defined image reference. Image references
are defined using syntax identical to link references:

[id]: url/to/image "Optional title attribute"

i look markdown doc see image syntax, but i write code not work:

![test][1]


[1]: http://i.stack.imgur.com/8wQ4J.jpg "你好"