Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
The :-moz-suppressed CSS pseudo-class matches elements representing images that were not loaded because loading images from that site has been blocked.
This selector is intended to be used mainly by theme developers.