[un1versal]

Spoilers is a English word, so it would have to be some image that expresses that in all languages. Text in images that cant be translated makes no sense, if that can be done then I suppose is by overlay some actual string over the default fallback image (in a bigger font size) and have that translated, then sure.

By using a default image only the settings explanation could also inform users of this fact anyway that the image show is not for lack of a real thumb is because its a potential spoiler.