inheriting classes

[PT Exorcist]

i have the following class:

    public class bTab : System.Windows.Forms.TabPage
    {
        ///<summary>A Struct which holds info for some TabPage functions</summary>
        public struct SIZE
        {
            private int _rowNumber;
            private int _rowPerLine;
            private int _spaceBetweenRow;
            private int _borderSize;
            private int _fileSize;

            /// <summary>Total Number of Files</summary>
            public int rowNumber
            {
                get
                {
                    return _rowNumber;
                }
                set 
                {
                    _rowNumber = value;
                }
            }


            /// <summary>Number of Files per Line</summary>
            public int rowPerLine
            {
                get
                {
                    return _rowPerLine; 
                }
                set 
                { 
                    _rowPerLine = value;
                }
            }


            /// <summary>Space between each File</summary>
            public int spaceBetweenRow
            {
                get
                {
                    return _spaceBetweenRow;
                }
                set
                {
                    _spaceBetweenRow = value;
                }
            }


            /// <summary>Size of right and left Border</summary>
            public int borderSize
            {
                get
                {
                    return _borderSize;
                }
                set
                {
                    _borderSize = value;
                }
            }


            /// <summary>Size of the PictureBox</summary>
            public int fileSize
            {

                get
                {
                    return _fileSize;
                }
                set
                {
                    _fileSize = value;
                }
            }
        }


        /// <summary>
        /// Default constructor for the class
        /// </summary>
        /// <param name="tabName">Tab text caption</param>
        public bTab(string tabName)
        {
            this.Text = tabName;
        }

        /// <summary>
        /// A collection of all the images displayed in current Tab
        /// </summary>
        public images Images = new images(); 

and then this other class that should appear inside this first:

    class images : CollectionBase
    {
        private object mother;

        /// <summary>
        /// A collection of all the images displayed in current Tab
        /// </summary>
        /// <param name="sender">A reference of the mother Tab</param>

        public images(object sender)
        {
            mother = sender;
        }

        /// <summary>
        /// Adds an new Image to the current Tab
        /// </summary>
        /// <param name="tabUrl">The Url of the image to be displayed</param>
        public void Add(string tabUrl)
        {
            List.Add(tabUrl);
            System.Windows.Forms.Button button = new System.Windows.Forms.Button();
            ((bTab)mother).Controls.Add(button);
            button.Visible = true;
            button.Top = 0;
            button.Left = 0;
        }
    } 

the deal here is that i want an inherited class from TabPage of the controlPanel...and i want that it has a collection inside that when i add an item to it it automaticaly adds too an button to the tab...i dont know if i am explaining well...

hmm the problem is that i'm getting the following error:
C:\Documents and Settings\JBRANCO\My Documents\Visual Studio Projects\deviation\panelClass.cs(101): Inconsistent accessibility: field type 'deviation.images' is less accessible than field 'deviation.bTab.Images'