This Add-on provides the ability to change the image setting permissions.default.image easily.
The possible settings are:
1 Allow all images to load, regardless of origin. (Default)
2 Block all images from loading. (red x)
3 Prevent third-party images from loading. (red border)
Note: If you deinstall this Add-on make sure the setting 1 (Allow all images to load, regardless of origin.) is active or use the option over menu "Edit" → "options" → tab "contents" → check box "load images".