I am looking for a way to open a TIFF and determine what compression it was saved in (LZW, JPEG, none, etc.).  Thank you for your time.

Bump. 

Hi,

There has a method to open tiff file with HttpHandler:

using System;
using System.Web;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;

namespace MyHandler
{
    /// <summary>
    /// Summary description for NewHandler.
    /// </summary>
    public class NewHandler : IHttpHandler
    {
        int Width = 0;
        int Height = 0; 
        public void ProcessRequest(HttpContext context)
            {
                if (context.Request.Params["height"] != null)
                {
                    try
                    {
                        Height = int.Parse(context.Request.Params["height"]);
                    }
                    catch
                    {
                        Height = 0;
                    }
                }
                if (context.Request.Params["width"] != null)
                {
                    try
                    {
                        Width = int.Parse(context.Request.Params["width"]);
                    }
                    catch
                    {
                        Width = 0;
                    }
                }
                if (Width <= 0 && Height <= 0)
                {
                    context.Response.Clear();
                    context.Response.ContentType = getContentType(context.Request.PhysicalPath); context.Response.WriteFile(context.Request.PhysicalPath);
                    context.Response.End();
                }
                else
                {
                    context.Response.Clear();
                    context.Response.ContentType = getContentType(context.Request.PhysicalPath);
                    byte[] buffer = getResizedImage(context.Request.PhysicalPath, Width, Height);
                    context.Response.OutputStream.Write(buffer, 0, buffer.Length);
                    context.Response.End();
                }
            }
        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
        byte[] getResizedImage(String path, int width, int height)
        {
            Bitmap imgIn = new Bitmap(path);
            double y = imgIn.Height;
            double x = imgIn.Width;
            double factor = 1;
            if (width > 0)
            {
                factor = width / x;
            }
            else if (height > 0)
            {
                factor = height / y;
            }
            System.IO.MemoryStream outStream = new System.IO.MemoryStream();
            Bitmap imgOut = new Bitmap((int)(x * factor), (int)(y * factor));
            Graphics g = Graphics.FromImage(imgOut);
            g.Clear(Color.White);
            g.DrawImage(imgIn, new Rectangle(0, 0, (int)(factor * x), (int)(factor * y)), new Rectangle(0, 0, (int)x, (int)y), GraphicsUnit.Pixel);
            imgOut.Save(outStream, getImageFormat(path));
            return outStream.ToArray();
        }
        string getContentType(String path)
        {
            switch (Path.GetExtension(path))
            {
                case ".bmp": return "Image/bmp";
                case ".gif": return "Image/gif";
                case ".jpg": return "Image/jpeg";
                case ".png": return "Image/png";
                case ".tif": return "Image/tiff";    
                default: break;
            }
            return "";
        }
        ImageFormat getImageFormat(String path)
        {
            switch (Path.GetExtension(path))
            {
                case ".bmp": return ImageFormat.Bmp;
                case ".gif": return ImageFormat.Gif;
                case ".jpg": return ImageFormat.Jpeg;
                case ".png": return ImageFormat.Png;
                case ".tif": return ImageFormat.Tiff;
                default: break;
            }
            return ImageFormat.Jpeg;               
         }
    }
}

<httpHandlers>
<add verb="*" path="*.tif" type="MyHandler.NewHandler"/>
<add verb="*" path="*.bmp" type="MyHandler.NewHandler"/>
<add verb="*" path="*.jpg" type="MyHandler.NewHandler"/>
<add verb="*" path="*.gif" type="MyHandler.NewHandler"/>
<add verb="*" path="*.png" type="MyHandler.NewHandler"/>	
</httpHandlers>

 If there have been any misunderstanding, please let me know.