final/src/BufferedImageWrapper.java

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.IndexColorModel;
import java.awt.image.WritableRaster;
import java.io.*;
import java.util.Hashtable;

public class BufferedImageWrapper implements Serializable {
    transient public BufferedImage image;
    public String imageString;
    public Boolean flipImage = false;

    public BufferedImageWrapper(int width, int height, int imageType) {
        image = new BufferedImage(width, height, imageType);
    }

    public BufferedImageWrapper(int width, int height, int imageType, IndexColorModel cm) {
        image = new BufferedImage(width, height, imageType, cm);
    }

    public BufferedImageWrapper(ColorModel cm, WritableRaster raster, boolean isRasterPremultiplied, Hashtable<?, ?> properties) {
        image = new BufferedImage(cm, raster, isRasterPremultiplied, properties);
    }

    public BufferedImageWrapper(BufferedImage image) {
        this.image = image;
    }

    public BufferedImageWrapper(String imageString) throws IOException {
        image = GamePanel.getImage(imageString);
        this.imageString = imageString;
    }

    public BufferedImageWrapper(String imageString, boolean flip) throws IOException {
        BufferedImage temporaryImage = GamePanel.getImage(imageString);
        if (flip) {
            image = GamePanel.flipImageHorizontally(temporaryImage);
        } else {
            image = temporaryImage;
        }
        flipImage = flip;
        this.imageString = imageString;
    }

    public BufferedImageWrapper() {}

    @Serial
    private void writeObject(ObjectOutputStream out) throws IOException {
        out.writeObject(flipImage);
        if (imageString != null) {
            out.writeObject(imageString);
        } else {
            ImageIO.write(image, "png", out); // png is lossless
        }
    }

    @Serial
    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
        Object o;
        flipImage = (Boolean)in.readObject();
        o = in.readObject();
        if (o instanceof String) {
            BufferedImage temporaryImage;
            this.imageString = (String)o;
            temporaryImage = GamePanel.getImage(imageString);
            if (flipImage) {
                image = GamePanel.flipImageHorizontally(temporaryImage);
            } else {
                image = temporaryImage;
            }
        } else {
            image = ImageIO.read(in);
        }
    }
}