Suresh, One thing you can do is use [IMG] tags from a URL. Upload your image to photobucket or flikr or any other photo hosting site and then you would use [IMG]your picture URL goes here[/IMG]........ you can add text below as long as you are typing outside the bracketed tags. An example of this
This is my example image
This is my caption below the image.
you can do this very easily by clicking the box that has what looks like mountains a sun and yellow sky in it. Click on that then copy and paste the URL to where you picture is.
If this is not clear let me know and I will do my best to clarify or someone else can explain better.