This extension allows you to download with a single click images from sites based on the Danbooru engine, such as safebooru.org. You can set up the file path based on the tags from the image, such as %artist% or %copyright%.
You can also set up a whitelist and automatically download all the images you browse that contain any given tag.
You can set it up the other way around as well, have a tags blacklist and autodownload all the images you browse except those on said blacklist.
UPDATE (yet again): Latest version should fix the toolbar button issues. To comply with Firefox's nomenclature standards, I changed the preferences' names, so you may have to re-configure your details. If you have lots of preferences, you can browse to your profile folder, open prefs.js and replace "danbooru.downloader." to "extensions.danboorudownloader."