Droopy is described as 'Say you’re chatting with a friend on MSN Messenger (perhaps with the excellent pidgin ?). She wants to send you amazing photos she took last week-end, so she uses Messenger file transfer. Unfortunately, the zip file is over 50 MB and it’s painfully slow' and is a Web Server in the backup & sync category. There are five alternatives to Droopy for a variety of platforms, including Windows, Linux, Mac, BSD and Self-Hosted apps. The best Droopy alternative is HFS 2 (HTTP File Server), which is both free and Open Source. Other great apps like Droopy are HFS 3 (HTTP File Server), PHFS ~ Python HTTP File Server, weborf and mini_httpd.
Downloading multiple files is easier with weborf than with droopy. Although I did not find the option to download a directory (except in archived form).