Code:

uses

UrlMon;

function DownloadFile(SourceFile, DestFile: string): Boolean;

begin

try

   Result := UrlDownloadToFile(nil, PChar(SourceFile), PChar(DestFile), 0,

     nil) = 0;

except

   Result := False;

end;

end;

procedure TForm1.Button1Click(Sender: TObject);

var

k, p: Integer;

Source, dest, ext: string;

begin

for k := 0 to WebBrowser1.OleObject.Document.Images.Length - 1 do

begin

   Source := WebBrowser1.OleObject.Document.Images.Item(k).Src;

   p := LastDelimiter('.', Source);

   ext := UpperCase(Copy(Source, p + 1, Length(Source)));

   if (ext = 'GIF') or (ext = 'JPG') then

   begin

     p  := LastDelimiter('/', Source);

     dest := ExtractFilePath(ParamStr(0)) + Copy(Source, p + 1,

       Length(Source));

     DownloadFile(Source, dest);

   end;

end;

end;