在图片上画线出现异常

在图片上画线出现错误 求助！
在Image中画线，我用Image1-> Canvas-> MoveTo，Image1-> Canvas-> LineTo方法，提示出错“can   only   modify   an   image   if   it   contains   a   bitmap”
求助   究竟该怎么画线啊？谢谢啦

------解决方案--------------------
Image中要么不包含图片, 要么只包含bmp图片.
------解决方案--------------------
不要直接加载bitmap，采用画图的方式，先画图，再画线
Graphics::TBitmap *BrushBmp = new Graphics::TBitmap;
BrushBmp-> LoadFromFile( "E:\\1.bmp ");
Image1-> Canvas-> Brush-> Bitmap = BrushBmp;
Image1-> Canvas-> FillRect(Rect(0,0,Image1-> Width,Image1-> Height));
Image1-> Canvas-> Brush-> Style=bsClear;
Image1-> Canvas-> Pen-> Color=clRed;
Image1-> Canvas-> MoveTo(10,10);
Image1-> Canvas-> LineTo(100,100);
delete BrushBmp;