Upload de arquivos - Controlar dimensão

import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.swing.ImageIcon;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class Thumbnail {
    /**
     * Reads an image in a file and creates
     * a thumbnail in another file.
     * @param orig The name of image file.
     * @param thumb The name of thumbnail file.
     * Will be created if necessary.
     * @param maxDim The width and height of
     * the thumbnail must
     * be maxDim pixels or less.
     */

    public boolean precisaRedimensionar(byte[] img, int tamanhoMax){
        boolean tamanho = false;
        Image inImage = new ImageIcon(img).getImage();

        if ( (inImage.getWidth(null) > tamanhoMax) || (inImage.getHeight(null) > tamanhoMax) ) {
            tamanho = true;
        }
        return tamanho;
    }

    public ByteArrayOutputStream createThumbnail(byte[] orig, int maxDim) {
        ByteArrayOutputStream btImage = new ByteArrayOutputStream();
        try {
            // Get the image from a file.
            Image inImage = new ImageIcon(orig).getImage(); //posso passar um array de bytes (no construtor ImageIcon)
            // Determine the scale.
            double scale = (double)maxDim/(double)inImage.getHeight(null);
            if (inImage.getWidth(null) > inImage.getHeight(null)) {
                scale = (double)maxDim/(double)inImage.getWidth(null);
            }

            // Determine size of new image.
            //One of them
            // should equal maxDim.
            int scaledW = (int)(scale*inImage.getWidth(null));
            int scaledH = (int)(scale*inImage.getHeight(null));

            // Create an image buffer in
            //which to paint on.
            BufferedImage outImage = new BufferedImage(scaledW, scaledH, BufferedImage.TYPE_INT_RGB);

            // Set the scale.
            AffineTransform tx = new AffineTransform();

            // If the image is smaller than
            //the desired image size,
            // don't bother scaling.
            if (scale < 1.0d){
                tx.scale(scale, scale);
            }

            // Paint image.
            Graphics2D g2d = outImage.createGraphics();
            g2d.drawImage(inImage, tx, null);
            g2d.dispose();

            // JPEG-encode the image
            JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(btImage);
            encoder.encode(outImage);

            btImage.close();

        } catch(IOException e){
            e.printStackTrace();
        }
        return btImage;
    }

}