How can we increase nokia5200vga camera to megapixels?

Answer 1

You can't. The no of pixels a camera has is determined at its manufacture. To get more pixels you'd have to replace the actual plate at the bottom of the camera that catches the incoming light. And that's not doable outside a very specialized workshop.

Answer 2

Camera pixels are hard-wired into the image sensor. All you can do is buy a newer model.

However if you are desperate to increase the apparent sharpness or size of a picture you can buy specialized software that can add pixels using some sort of fractal logic.

While there is no way to add pixels the camera would have recorded if it was just a higher megapixel camera to begin with - this software can realistically enlarge a picture and fill the gaps with more of the same as the pixels surrounding it.