function GetIcon(FileName: PChar; Directory: Boolean): TIcon;
var
//You need a variable of type "_SHFILEINFOA" :
FileInfo: _SHFILEINFOA;
Attrib: DWord;
Flags: Cardinal;
begin
Flags:=SHGFI_ICON;
If Directory then Attrib:=FILE_ATTRIBUTE_DIRECTORY else Attrib:=0;
SHGetFileInfo(FileName, Attrib, FileInfo, SizeOf(FileInfo), Flags);
Result:=TIcon.Create;
Result.Handle:=FileInfo.hIcon;
end; exemple :

var filename : string;
Image1 : timage;
Image2 : timage;

begin
Filename:='c:\toto\monfichier.xls';
image2.Picture.Icon:=geticon(pchar(Filename), false);
Filename:='C:\documents and Settings\Propriétaire\Mes documents\';
image1.Picture.Icon:=geticon(pchar(Filename), true);
end;