This script adds a simple "download" button to images on Bluesky.

It uses Bluesky's API to acquire a higher quality, less compressed version of the image than the Bluesky feeds provide, and also gives the downloaded image file a useful filename. You can customize the filename format a bit by editing the script to your liking.

I based this script on TwitterImg Downloader, though Bluesky Image Downloader barely resembles the original.