I guess it does what it says on the box and is a darn sight more convenient than manually setting the permission.default.image attribute. However, it would be nice to introduce a feature to display selected images in-situ, on the webpage, possibly view a right-click option?
Just noticed that even though the icon shows images are blocked, when starting Firefox (Win 10 Pro 64-bit, FF 66.0.3) images are still displayed. I need to toggle the icon on/off to get it to work. Also, the "Reload on toggle" option doesn't stay checked. When I set it, then exit the add-ons page, then go in again, it's back to unchecked.