procedure TForm1.Button1Click(Sender: TObject);
var
  img: TImageEnView;
  ms, imgStream: TMemoryStream;
begin
  if Assigned(cxPageControl1.ActivePage) then
  begin
    ImageEnView := TImageEnView(cxPageControl1.ActivePage.Controls[0]);
    if Assigned(ImageEnView) then
    begin
      img := TImageEnView.Create(nil);
      try
        ms := TMemoryStream.Create;
        try
          imgStream := TMemoryStream.Create;
          try
            ImageEnView.IO.SaveToStreamJPEG(imgStream);
            imgStream.Position := 0;  // Important
            img.IO.LoadFromStreamJpeg(imgStream);
            ShowMessage(Format('Input Image size in bytes: %d', [imgstream.Size]));
            img.Proc.ImageResize(ImageEnView.IEBitmap.Width + 10, ImageEnView.IEBitmap.Height +
              10, iehCenter,
              ievCenter);
            img.IO.SaveToStreamJPEG(ms);
            ms.Position := 0; // Important
            ShowMessage(Format('Saved to memory stream, size=%d', [ms.Size]));
            ImageEnView.IO.LoadFromStreamJpeg(ms);
            ImageEnView.Update;
            UpdateStatusBar;
          finally
            imgStream.Free;
          end;
        finally
          ms.Free;
        end;
      finally
        img.Free;
      end;
    end;
  end;
end;