How to Add 'Comments' to a JPEG File Using C#

Question

Within the property window of a JPEG image, there is a tab called \'Summary\'. Within this tab, there is a field called \'Comments\' I would like to write some c# code which

Answer 1

A variant on Peter Kistler's solution to set Title, Subject and Comment. I found I had to create items as Unicode byte array (type 1) and the IDs for Title, Subject and Comment are the same as for EXIF XPTitle, XPSubject and XP Comment. sFileOut can be the same as sFile.

public static void SetWindowsTags2(string sFile, string sFileOut, string Title = "", string Subject = "", string Comment = "", bool bShowError = false)
    {
        try
        {

            // Retrieve the Image
            System.Drawing.Image originalImage = System.Drawing.Image.FromFile(sFile);

            // Get the list of existing PropertyItems. i.e. the metadata
            PropertyItem[] properties = originalImage.PropertyItems;

            /*foreach (PropertyItem propItem in properties)
            {
                string sTag = System.Text.Encoding.UTF8.GetString(propItem.Value);
                string sItem = sTag.Replace("\0", string.Empty);

                Debug.Print(propItem.Id.ToString() + ", " +  propItem.Type + ", " + sItem);
            }*/

            // Create a bitmap image to assign attributes and do whatever else..
            Bitmap bmpImage = new Bitmap((Bitmap)originalImage);

            // Don't need this anymore
            originalImage.Dispose();

            // Get / setup a PropertyItem
            PropertyItem item = properties[0]; // We have to copy an existing one since no constructor exists

            var itemData = System.Text.Encoding.Unicode.GetBytes(Title);
            itemData[itemData.Length - 1] = 0;// Strings must be null terminated or they will run together
            item.Type = 1; //Unicode Byte Array
            item.Id = 40091; // Title ID
            item.Len = itemData.Length; // Number of items in the byte array
            item.Value = itemData; // The byte array
            bmpImage.SetPropertyItem(item); // Assign / add to the bitmap


            itemData = System.Text.Encoding.Unicode.GetBytes(Subject);
            itemData[itemData.Length - 1] = 0; // Strings must be null terminated or they will run together
            item.Type = 1; //Unicode Byte Array
            item.Id = 40095; // subject
            item.Len = itemData.Length;
            item.Value = itemData;
            bmpImage.SetPropertyItem(item); // Assign / add to the bitmap


            itemData = System.Text.Encoding.Unicode.GetBytes(Comment);
            itemData[itemData.Length - 1] = 0; // Strings must be null terminated or they will run together
            item.Type = 1; ////Unicode Byte Array
            item.Id = 40092; // comment
            item.Len = itemData.Length;
            item.Value = itemData;
            bmpImage.SetPropertyItem(item); // Assign / add to the bitmap


            // Save the image
            bmpImage.Save(sFileOut, System.Drawing.Imaging.ImageFormat.Jpeg);

            //Clean up
            bmpImage.Dispose();

        }
        catch (Exception Ex)
        {

        }

    }