How to use com.atlassian.core.util.thumbnail

@Override
public String getMimeType()
{
  return thumbnail.getMimeType().name();
}

private AvatarImageDataProviderImpl(final InputStream uploadedImage, final Selection cropping)
    throws IOException
{
  // rather should accept image?
  this.uploadedImage = thumber.getImage(uploadedImage);
  this.cropping = cropping;
}

@Override
public int getHeight()
{
  return thumbnail.getHeight();
}

private Thumbnail createThumbnail(InputStream originalFile, File thumbnailFile, int maxWidth, int maxHeight, long thumbId, String fileName) throws IOException, FileNotFoundException
{
  // Load original image.
  Image originalImage = getImage(originalFile);
  // Create scaled buffered image from original image.
  BufferedImage scaledImage = scaleImage(originalImage, maxWidth, maxHeight);
  int height = scaledImage.getHeight();
  int width = scaledImage.getWidth();
  storeImage(scaledImage, thumbnailFile);
  return new Thumbnail(height, width, fileName, thumbId);
}

private Thumbnail createThumbnail(InputStream inputStream, File thumbnailFile, int maxWidth, int maxHeight, long thumbId, String fileName)
    throws IOException, ThumbnailRenderException {
  final BufferedImage thumbnailImage = scaleImage(maxWidth, maxHeight, inputStream);
  final int height = thumbnailImage.getHeight();
  final int width = thumbnailImage.getWidth();
  storeImage(thumbnailImage, thumbnailFile);
  return new Thumbnail(height, width, fileName, thumbId, mimeType);
}

private BufferedImage scaleImage(Image originalImage, int maxWidth, int maxHeight)
{
  return scaleImage(originalImage, determineScaleSize(maxWidth, maxHeight, originalImage));
}

private Thumbnail getThumbnail(File thumbnailFile, String filename, long thumbId) throws IOException
{
  if (thumbnailFile.exists())
  {
    final Image thumbImage = getImage(thumbnailFile);
    return new Thumbnail(thumbImage.getHeight(null), thumbImage.getWidth(null), filename, thumbId);
  }
  return null;
}

public BufferedImage scaleImage(int maxWidth, int maxHeight, InputStream imageStream) throws IOException {
  final ImageInputStream imageInputStream = ThumbnailUtil.getImageInputStream(imageStream);
  try {
    return scaleImage(maxWidth, maxHeight, imageInputStream);
  } finally {
    imageInputStream.close();
  }
}

@Override
public int getWidth()
{
  return thumbnail.getWidth();
}

@Override
public String getFilename()
{
  return thumbnail.getFilename();
}

@Override
public long getAttachmentId()
{
  return thumbnail.getAttachmentId();
}

public CroppingAvatarImageDataProviderFactoryImpl(final AvatarTagger avatarTagger, final ImageScaler scaler)
{
  this.scaler = scaler;
  thumber = new Thumber();
  this.avatarTagger = avatarTagger;
  this.targetFormat = "png";
}

/**
 * Returns the hash code for this <code>Thumbnail</code>.
 *
 * @return the hash code for this <code>Thumbnail</code>
 */
@Override
public int hashCode() {
  int result = super.hashCode();
  result = 31 * result + (mimeType != null ? mimeType.hashCode() : 0);
  result = 31 * result + (filename != null ? filename.hashCode() : 0);
  result = 31 * result + (int) (attachmentId ^ (attachmentId >>> 32));
  return result;
}

/**
 * Notification of the properties of the image to use. Not used in this implementation.
 *
 * @param props The map of properties for this image
 */
public void setProperties(Hashtable props)
{
  createImage();
}

public ThumbnailDimension determineScaleSize(int maxWidth, int maxHeight, int imageWidth, int imageHeight) {
  return ThumbnailUtil.determineScaledDimensions(maxWidth, maxHeight, imageWidth, imageHeight);
}

@Override
public int hashCode()
{
  int result = attachment.hashCode();
  result = 31 * result + (thumbnail != null ? thumbnail.hashCode() : 0);
  return result;
}

public ImageFileOperations()
{
  this.thumber = new Thumber();
}

/**
 * Notification of the dimensions of the source image.
 *
 * @param w The width of the source image
 * @param h The height of the source image
 */
public void setDimensions(int w, int h)
{
  width = w;
  height = h;
  createImage();
}

public AvatarPickerHelperImpl(AvatarManager avatarManager,
    JiraAuthenticationContext authenticationContext,
    ApplicationProperties properties,
    VelocityRequestContextFactory requestContextFactory,
    UserUtil userUtil,
    final UniversalAvatarsService universalAvatarsService)
{
  this.avatarManager = avatarManager;
  this.authenticationContext = authenticationContext;
  this.applicationProperties = properties;
  this.requestContextFactory = requestContextFactory;
  this.userUtil = userUtil;
  this.universalAvatarsService = universalAvatarsService;
  this.thumber = new Thumber(Thumbnail.MimeType.PNG);
}

public void setColorModel(ColorModel model)
{
  colorModel = model;
  createImage();
}