dattasaurabh82, you resurrected two year-old topics that seems unrelated to your problem as you explain it.
It is good you did research before asking, but avoid posting three times the same question in different places, it only dilutes efforts to help you.
You don't mention saving to a Web server nor having to choose a random image, you just are talking about saving a given image to a local folder, which can be done with save() or saveFrame(). Unless I miss something.

So I deleted the comments you added on the old topics, so we can concentrate on your problem as explained here.

Thanks Administrator.
I just did that thinking it would cause a bit more exposure. Any ways sorry for doing so .
Can you by the way provide a solution to my quarry?

In addition to save(), as mentioned, you probably also need to use java.io.File, and its list() method to get the list of files at a given path.
Note that the sketchPath() function can be useful for you, too.

I'll post the code tomorrow after trying. Thanks for the suggestion. I may need a li'll help here as I'm not much of a programmer & that also in java advanced.