Bonjour,
Tu peux faire ceci :
public static void main(String[] args) throws IOException {
BufferedImage image = ImageIO.read(new File("D:/image.png"));
int w = image.getWidth();
int h = image.getHeight();
BufferedImage img = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
int[] r = new int[w * h];
image.getRGB(0, 0, w, h, r, 0, w);
img.getRaster().setDataElements(0, 0, w, h, r);
for (int i = 0; i < w; i++) {
for (int j = 0; j < h; j++) {
img.setRGB(w - i - 1, j, image.getRGB(i, j));
}
}
ImageIO.write(img, "png", new File("D:/res.png"));
}