import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class Pixelate 
{
	
	public void pixelateFile(int pixelSize, File inputFile, File outputFile) throws IOException
	{
		// get a BufferedImage object from file
		BufferedImage bufferedImage = ImageIO.read(inputFile);
		
		// loop through the image and produce squares pixelSize*pixelSize
		for(int w = 0 ; w < bufferedImage.getWidth() ; w+=pixelSize)
		{
			for(int h = 0 ; h < bufferedImage.getHeight() ; h+=pixelSize)
			{
				Color pixelColor = new Color(bufferedImage.getRGB(w, h));
				
				Graphics graphics = bufferedImage.getGraphics();
				graphics.setColor(pixelColor);
				graphics.fillRect(w, h, pixelSize, pixelSize);
			}
		}
		
		// output file
		ImageIO.write(bufferedImage, "jpg", outputFile);
		
	}

}