Add image support in web2.0 app

I added image support in the web2.0 app. It means that users can uploads image files besides regular text files. Users can attach tags, description and name when uploading an image. Other users can post comment/rating about the image.

When an image is uploaded, it will be stored somewhere at server side. Moreover, it can be retrieved by accessing a URL. In other words, the server generates a URL which can be used to access that image. When a user tries to retrieve the image, it will be displayed in browser by using img elment.

Currently, I am using suffix of file name to judge type of record (image or text). The advantage is that user intervening is not needed. Drawback is that sometimes suffixes are not accurate. It may be better to use MIME type which is specified when user uploads an object.