This is a very simple fork of mmis1000's script found here:https://greasyfork.org/en/scripts/2831-pixiv-animated-image-downloader-and-gif-convert
The only changes are to the language of the script's pop-up window interface and tooltips which are now in abbreviated English due to space constraints and me being too lazy to mess with the UI size.
1. Click the button to the left of the 'expand image' button on the top right corner of the image. (See Fig 1)
2. Choose your desired settings in the pop-up window: (See Fig 2)
-'Sml' for the default size image; 'Lrg' for the original size image
-'Zip' to download a zip containing all of the separate frames; 'gif' to automatically generate an animated gif
-'DL' to send the generated zip or gif file to the browser as a download; 'View' to open the gif in a pop-up screen.
NOTE: I have not tested what selecting 'view' and 'zip' at the same time does. Use at your own risk. Not responsible for crashes, loss of data, releasing of magic blue smoke, fire, electrocution, explosions, injury or death, etc from attempting to send a zip to the image viewer. You have been warned.
Tested on May 10, 2018 on Palemoon 27.7.2 with Greasemonkey 3.9.2