For more complex galleries, addons dedicated to this purpose exist. Therefore, you do not actually need an addon to download most thumbnail galliers. Most browsers download link targets when alt-clicking on links, and most thumbnail galleries link each thumbnail to its full size source. This is an unfortunately but deliberately omitted feature. This addon downloads the image you directly interact with, i.e. How does it work on thumbnail galleries?.
*uncertain support in Firefox: addon will automatically disable feature until supported 'image downloaded' effect for visual feedback can be disabled.use filters to limit functionality if it gets in the way.rename downloaded images using patterns and variables for better mass organization *.trigger a notification on successful downloads.select page content (or point at an image) and use the context menu.drag and drop an image onto the hover button.hover over them and click the button that appears.I have mild intentions to reimplement the core functionality of CSL, IBCP, and DID as public userscripts. I do have a greasyfork account and may publish works there in the future. The addon will remain available for download as long as the store allows, and the source on gitlab will also remain available to fork.
I'm shelving this project due to lack of interest/utility and too much burden.