I have not check it before posting. Sorry. I have created another solution
for you. Hope this make a trick.
using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using System.ComponentModel.Design;

namespace WindowsApplication6 {

public partial class Form1 : Form {

public Form1() {

InitializeComponent();

}

}

public class MyImageListDesigner :
System.ComponentModel.Design.ComponentDesigner {

public override void InitializeNewComponent(System.Collections.IDictionary
defaultValues) {

IDesignerHost host = GetService(typeof(IDesignerHost)) as IDesignerHost;

host.Container.Add(((MyImageList)Component).ImageList);

base.InitializeNewComponent(defaultValues);

}

}

[Designer("WindowsApplication6.MyImageListDesigner")]

public class MyImageList : Component {

ImageList list;

public MyImageList() {

list = new ImageList();

}

public ImageList ImageList {

get { return list; }

set { list = value; }

}

}

}