Image Avatar download Optimization

1. Http Inputstream or byte[] ?
2. Image Process? download avatar pageName if many wikis?

Conclusion:
1. I have review my code again and again. And maybe no need to change. because the network response return an inputstream which needs to be close, So I just InputStream -> byte[] (close the network stream) -> ByteArrayInputStream(No need to close aha), maybe it's reasonable because it can avoid forgetting to close inputstream, quickly release the network resources.
2. downloadAvatar(String pageName, String imageName). It seems that all the user is in the wikis/xwiki, so no need to change.