There is currently no reliable way of annotating media objects with, for instance, which of a light or dark theme they have a better affinity with. The information could be used by applications, including but not limited to search engines, to select the best variant of an image to render for their users.

Some current properties could be abused for the purpose. For instance, either pattern or version could be set to dark to signal the media object has a better affinity with a dark theme, but this use case is not the primary motivator for the existence of either properties and there is no clear criterium for choosing which to use for this.

Beyond the limited concept of a single light theme and a single dark theme, where luminance is the only dimension, there could also be situations where variants have a better affinity to certain chroma values.

A new property of MediaObject could support these use cases or point to another resource of a schema offering a generalization of what a "surrounding context" might mean, whether it relates to visual perception as above or to other kinds of contexts.