Given a jpeg image as InputStream, resize it and return another InputStream.

ResizeImage.java

// formatName: the image format name (jpeg, png)
public static InputStream resizeImage(InputStream inputStream, int width, int height, String formatName) throws IOException {
    BufferedImage sourceImage = ImageIO.read(inputStream);
    Image thumbnail = sourceImage.getScaledInstance(width, height, Image.SCALE_SMOOTH);
    BufferedImage bufferedThumbnail = new BufferedImage(thumbnail.getWidth(null),
            thumbnail.getHeight(null),
            BufferedImage.TYPE_INT_RGB);
    bufferedThumbnail.getGraphics().drawImage(thumbnail, 0, 0, null);
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    ImageIO.write(bufferedThumbnail, formatName, baos);
    return new ByteArrayInputStream(baos.toByteArray());
}

thank's

Does this only work for JPEG or any kind of image?

It works for other formats as well. For instance, I have tested with png. I have updated the gist.

Muito Obrigado.