The BITMAPINFOHEADER contains information about the color space and dimensions of a DIB.

C# Definition:

[StructLayout(LayoutKind.Sequential)]
public struct BITMAPINFOHEADER
{
    public uint  biSize;
    public int   biWidth;
    public int   biHeight;
    public ushort   biPlanes;
    public ushort   biBitCount;
    public uint  biCompression;
    public uint  biSizeImage;
    public int   biXPelsPerMeter;
    public int   biYPelsPerMeter;
    public uint  biClrUsed;
    public uint  biClrImportant;

    public void Init()
    {
        biSize = Marshal.SizeOf(this);
    }
}

VB Definition:

StructLayout(LayoutKind.Explicit)> Public Structure BITMAPINFOHEADER
     <FieldOffset(0)>  Public biSize As Int32
     <FieldOffset(4)>  Public biWidth As Int32
     <FieldOffset(8)>  Public biHeight As Int32
     <FieldOffset(12)> Public biPlanes As Int16
     <FieldOffset(14)> Public biBitCount As Int16
     <FieldOffset(16)> Public biCompression As Int32
     <FieldOffset(20)> Public biSizeImage As Int32
     <FieldOffset(24)> Public biXPelsperMeter As Int32
     <FieldOffset(28)> Public biYPelsPerMeter As Int32
     <FieldOffset(32)> Public biClrUsed As Int32
     <FieldOffset(36)> Public biClrImportant As Int32
End Structure

User-Defined Field Types:

None.

Notes:

This is one of those structures where the size of the structure must be set before the structure

can be used by the API. A user should call the Init() method before using this structure in an API call.

(Thanks to Mike I for the VB.NET definition).

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdi/bitmaps_1rw2.asp