引用ComObj单元
uses ComObj;

procedure TForm1.Button1Click(Sender: TObject);
Var FExcel :OleVariant; //excel应用程序
FWorkBook :OleVariant; //工作表
FWorksheet:OleVariant; //工作薄
FPicture:OleVariant;
TmpStr:String;
begin
FExcel:= CreateoleObject( "excel.Application");
FWorkBook:=FExcel.WorkBooks.Add; //新的工作表
FWorksheet:=FWorkBook.Worksheets[1];
FWorksheet.Select;

//插入图象并设置位置与大小
tmpstr:= "f:\1.jpg";
FPicture:=FWorksheet.Pictures.Insert(tmpstr);
FPicture.Left:=10;
FPicture.Top:=10;
FPicture.width:=200;
FPicture.height:=200;
FPicture:=null;
FExcel.visible:=true;
end;

在WINDOWS XP SP2 + DELPHI7.0 + EXCEL2003 测试通过