add image support, add indicator location up or down support

![Screenshot2](https://f.cloud.github.com/assets/696493/101797/cc5ab75a-68f2-11e2-8f68-f6aa45e99ee4.png)
![iOS 2013-1-28 10 28 28 ](https://f.cloud.github.com/assets/696493/101798/cf466270-68f2-11e2-938f-53e9b1b37505.png)