Reading Image Headers to Get Width and Height

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Threading;

namespace DevWilson
{
    public class ImageOrientationThreaded
    {
        private int imagesRemaining;

        public List<string> Landscapes { get; private set; }

        public void GetLandscapeThreaded(List<string> paths)
        {
            this.Landscapes = new List<string>();
            this.imagesRemaining = paths.Count;

            foreach (string path in paths)
            {
                // add each path as a task in the thread pool
                ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadCallback), path);
            }


            // wait until all images have been loaded
            lock (this.Landscapes)
            {
                Monitor.Wait(this.Landscapes);
            }
        }

        private bool IsLandscape(string path)
        {
            using (Bitmap b = new Bitmap(path))
            {
                return b.Width > b.Height;
            }
        }

        private void ThreadCallback(object stateInfo)
        {
            string path = (string)stateInfo;
            bool isLandscape = this.IsLandscape(path);
           
            lock (this.Landscapes)
            {
                if (isLandscape)
                {
                    this.Landscapes.Add(path);
                }

                imagesRemaining--;

                if (imagesRemaining == 0)
                {
                    // all images loaded, signal the main thread
                    Monitor.Pulse(this.Landscapes);
                }
            }
        }
    }
}