The Imagelist streaming implementation and other features of the Coolbar and Toolbar have changed between Internet Explorer 3.02 and Internet Explorer 4. Applications using Win32 common controls developed under Internet Explorer 4.0 may not work correctly under Internet Explorer 3.02 (and vice-versa). The way to work around the imagelist streaming problem is to not stream the images to the .dfm. Instead, place the bitmaps in a resource file, then load them into the imagelist at runtime using the following code:

procedure LoadResourcedBMP(ID: string; Images: TImageList);
var
  B: TBitmap;
begin
  B := TBitmap.Create;
  try
    B.LoadFromResourceName(hInstance, ID);
    Images.AddMasked(B, B.TransparentColor);
  finally
    B.Free;
  end;
end;