Por que isso acontece?
Facebook has sent me a Cease & Desist notice (click here to view) stating that PhotoJacker/FacePAD violates Section 3.2 of their Statement of Rights and Responsibilities:
You will not collect users’ content or information, or otherwise access Facebook, using automated means (such as harvesting bots, robots, spiders, or scrapers) without our permission. (Section 3.2)
PhotoJacker/FacePAD, is in some way, a scraper, since it allows the end-user to download photos (that the user can manually download by right-clicking on the photo and pushing saved target/image as…) from Facebook to their computer in an expeditious manner. For the record, scraping is a very loosely defined term, and not all definitions I’ve read make it sound like PhotoJacker/FacePAD is a scraper.
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Regardless, I am currently a full time student, and I really don’t have the time to deal with this problem. Therefore, I have decided to comply with Facebook’s takedown notice. The program has been removed from Mozilla, and therefore, it can no longer be accessed or downloaded.
Fonte: PhotoJacker - Cease & Desist / Aviso de remoção do Facebook
Qualquer outra alternativa?
Bem, o downgrade é uma opção se você ainda tiver o plugin por aí. Caso contrário, não acho que você encontrará plugins que ainda estejam funcionando. Eu acho que o facebook entrou em contato com todos os criadores desses plugins para evitar que eles estejam disponíveis e funcionando.
Outra solução poderia ser instalar um segundo firefox (aquele com o plugin quando ele ainda estava funcionando). Supondo que você não tenha que baixar álbuns inteiros todos os dias, isso deve ser gerenciável.