use mshtml, ActiveX, COMObj, idURI,IdHTTP...

procedure GetImageLinks(AURL: string; AList: TStrings);
var
  IDoc: IHTMLDocument2;
  strHTML: string;
  v: Variant;
  x: Integer;
  ovLinks: OleVariant;
  DocURL: string;
  URI: TidURI;
  ImgURL: string;
  idHTTP: TidHTTP;
begin
  AList.Clear;
  URI := TidURI.Create(AURL);
  try
    DocURL := 'http://' + URI.Host;
    if URI.Path <> '/' then
      DocURL := DocURL + URI.Path;
  finally
    URI.Free;
  end;
  Idoc := CreateComObject(Class_HTMLDocument) as IHTMLDocument2;
  try
    IDoc.designMode := 'on';
    while IDoc.readyState <> 'complete' do
      Application.ProcessMessages;
    v      := VarArrayCreate([0, 0], VarVariant);
    idHTTP := TidHTTP.Create(nil);
    try
      strHTML := idHTTP.Get(AURL);
    finally
      idHTTP.Free;
    end;
    v[0] := strHTML;
    IDoc.Write(PSafeArray(System.TVarData(v).VArray));
    IDoc.designMode := 'off';
    while IDoc.readyState <> 'complete' do
      Application.ProcessMessages;
    ovLinks := IDoc.all.tags('IMG');
    if ovLinks.Length > 0 then
    begin
      for x := 0 to ovLinks.Length - 1 do
      begin
        ImgURL := ovLinks.Item(x).src;
        // The stuff below will probably need a little tweaking
        // Deteriming and turning realtive URLs into absolute URLs
        // is not that difficult but this is all I could come up with
        // in such a short notice.
        if (ImgURL[1] = '/') then
        begin
          // more than likely a relative URL so
          // append the DocURL
          ImgURL := DocURL + ImgUrl;
        end
        else
        begin
          if (Copy(ImgURL, 1, 11) = 'about:blank') then
          begin
            ImgURL := DocURL + Copy(ImgUrl, 12, Length(ImgURL));
          end;
        end;
        AList.Add(ImgURL);
end;
    end;
  finally
    IDoc := nil;
  end;
end;

（出处：DelphiFans.com）