How to populate image tree faster.

Hi...could someone help me figure out how load my thumbnails either faster....or just in the background so I can still use my UI? I have a form that loads/imports photos and it takes about 5 to 6 seconds to load thumbnails of just average sized photos. I'm using a progress bar which is just sitting in the middle of my UI until the thumbnails load. Can someone help out? Here is my populateTree function: (I'm using a e.Graphics.DrawImage() in my Utilities.cs to draw the actual thumbnail)

Code:

private void PopulateTree()

        {

            string[] albumList = Directory.GetFiles(_directoryCurrentUser, "*" + ".album");

            treeView_Albums.Nodes.Clear(); //Clears nodes so they can be added again

            int totalAlbums = albumList.Count();

 

            //Loop through each found file and add it to tree. Set its path and show the file name

            for (int i = 0; i < totalAlbums; i++)

            {

                var node = new TreeNode

                               {

                                   Name = albumList[i],

                                   Text =

                                       Utilities.getNameFromPath(albumList[i]) +

                                       _albumData.AlbumGetPhotoCount(albumList[i]),

                                   ImageIndex = 0

                               };

                treeView_Albums.Nodes.Add(node);

 

                if (node.Name == _albumData.FilePath) //Highlight if album node is open

                {

                    node.BackColor = Color.LightGray;

                }

            }

        }

Using VSPro2010
Thanks in advance....

Before populating the tree, call BeginUpdate Method. When you're done populating it, call EndUpdate Method.