source: lost-perception/utils/ConvertToPNG.java

package utils;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.awt.image.RenderedImage;
import javax.imageio.ImageIO;
import java.io.File;

public class ConvertToPNG {
    public static void main(final String[] args) {
        final String path = "D:/workspace/LostHaven2/images/creatures/";
        final String crName = "orc";
        final String[] actions = { "attacking", "beenhit", "dying", "walking", "standing" };
        for (int x = 0; x < actions.length; ++x) {
            final File dir = new File(String.valueOf(path) + crName + "/" + actions[x]);
            final File[] contents = dir.listFiles();
            File[] array;
            for (int length = (array = contents).length, i = 0; i < length; ++i) {
                final File curFile = array[i];
                final String curName = curFile.getName();
                final String newName = String.valueOf(curName.substring(0, curName.indexOf("."))) + ".png";
                try {
                    final BufferedImage img = ImageIO.read(new File(String.valueOf(path) + crName + "/" + actions[x] + "/" + curName));
                    ImageIO.write(img, "png", new File(String.valueOf(path) + crName + "/" + actions[x] + "/" + newName));
                    curFile.delete();
                }
                catch (IOException ioe) {
                    ioe.printStackTrace();
                }
            }
        }
    }
}