How to improve the performance of g.drawImage() method for resizing images

Question

I have an application where users are able to upload pictures in albums but naturally the uploaded images need to be resized so there are also thumbs available and the shown

Answer 1

I'm using code similar to the following to scale images, I removed the part that deals with preserving the aspect ratio. The performance was definitely better than 10s per image, but I don't remember any exact numbers. To archive better quality when downscaling you should scale in several steps if the original image is more than twice the size of the wanted thumbnail, each step should scale the previous image to about half its size.

public static BufferedImage getScaledImage(BufferedImage image, int width, int height) throws IOException {
    int imageWidth  = image.getWidth();
    int imageHeight = image.getHeight();

    double scaleX = (double)width/imageWidth;
    double scaleY = (double)height/imageHeight;
    AffineTransform scaleTransform = AffineTransform.getScaleInstance(scaleX, scaleY);
    AffineTransformOp bilinearScaleOp = new AffineTransformOp(scaleTransform, AffineTransformOp.TYPE_BILINEAR);

    return bilinearScaleOp.filter(
        image,
        new BufferedImage(width, height, image.getType()));
}