order the events within button_Click

Question

I am trying to get events to occur one at a time within my button_Click, but for some reason everything seems to wait to run until everything is complete. For instance image changes don't occur until everything else has occured.

private void button1_Click(object sender, EventArgs e)
    {
            pictureBox1.Image = Properties.Resources.running;
            iTunesAppClass itunes = new iTunesAppClass();
            IITLibraryPlaylist mainLibrary = itunes.LibraryPlaylist;
            IITTrackCollection ittracks = mainLibrary.Tracks;


            List<string> files = new List<string>();
            List<string> musicfiles = new List<string>();
            List<string> badfiles = new List<string>();
            List<string> songlist = new List<string>();
            int state = ((int)itunes.PlayerState);

            string statestring = null;
            if (state < 1) { statestring = "Stopped"; };
            if (state == 1) { statestring = "Playing"; };

            if (state == 1)
            {
                do
                {
                    label5.Text = ("Pausing iTunes to maintain file integrity");
                    itunes.Pause();
                    state = (int)itunes.PlayerState;
                }
                while (state == 1);
            }
            if (state < 1) { statestring = "Stopped"; };
            if (state == 1) { statestring = "Playing"; };
            if (state != 1)
            {
                label5.Text = "Itunes is " + statestring;
            }

            string[] extensions = { "*.mp3", "*.mp4", "*.m4a", "*.m4v", "*.m4p", "*.m4b", "*.flac" };
            string filepath = label4.Text;
            foreach (string extension in extensions)
            {
                this.pictureBox1.Image = Properties.Resources.running;
                try
                {
                    files.AddRange(Directory.GetFiles(filepath, extension, SearchOption.AllDirectories));
                }
                catch (UnauthorizedAccessException) { }
            }

            foreach (string file in files)
            {
                try { string taglibfile = TagLib.File.Create(file).Tag.Title; musicfiles.Add(file); Console.WriteLine(taglibfile); }
                catch { badfiles.Add(file); }
            }
            XDocument baddoc = new XDocument
            (new XElement("Corrupt",
               badfiles.Select(badfile =>
               new XElement("File", badfile))));
            baddoc.Save(label4.Text + "\\badfiles.xml");
            // foreach(string musicfile in musicfiles)
            //{ String Title = (TagLib.File.Create(musicfile).Tag.Title); }
            this.pictureBox1.Image = Properties.Resources.skinitunes;
    }