To make give users an impression on how the application they are about to install will look like, screenshots are provided in the AppStream spec. But since not all upstream authors ship screenshots, there is a way for distributors to specify a server for screenshots provided by a 3rd-party.
Distributors provide a service like
debshots. They can either use the original
debshots web application, which does not only work for Debian but also any other distribution, or they can set up their own service which mimicks the
debshots API (OpenSUSE does that).
In order to make a new screenshot service known to software-centers, distributors need to place information about their webservice in the config file of libappstream, whis is usually located at /etc/appstream.conf.
The screenshot data will be inserted transparently into
AsScreenshot, if the distributor has set the configuration flag. Authors of software-centers don't need to take care of this implementation detail.
