Since 2019, it is possible to add structured data to files on Wikimedia Commons  (SDC = Structured Data on Commons), but adding structured 'depicts' annotations remains a challenging task, particularly since there is no strong guidance on use of standard controlled vocabularies. Also such vocabularies can't always meet the needs of highly diverse media collections and multi-lingual & multi-cultural contexts.
But there are possible pathways to create more structured and user-friendly workflows for the application of specialist vocabularies, such as Iconclass , when it comes to images of fine art in particular.
Myself (a UX designer & experienced Wikidata / Wikibase user), an art historian and DH researcher - Dr Karin de Wild, and the developer of the Iconclass Browser - Etienne Posthumus, have proposed a small new research grant to Wikimedia . Our goal is to research and prototype several routes to make the addition of standard Iconclass terms as structured data on Commons, as well as the reuse of these data statements, an easier and more intuitive task for users of Commons services, GLAM professionals who may have collections described with Iconclass codes already, or DH researchers who want to run queries against the Wiki Commons query service and discover interesting data correlations across works from multiple collections. This is framed as a research endeavor, rather than just a technical project, because we are aware Iconclass is not a perfect vocabulary, but working closely with the Iconclass community, and the international communities of Wikidata / Wiki Commons users, we will research how the vocabulary can better meet the needs of diverse use-cases, rather than just implementing it without effort to respond to justified critiques.
If this is something of interest to you, please review our application and consider leaving some feedback via the form . All feedback is much appreciated and will help us refine our proposal if we get to Stage II of the process, or help us apply for further funding opportunities in the future.
Many thanks and kind regards,
Dr. Lozana Rossenova
Researcher @ Open Science Lab, TIB Hannover
Wikibase Community Manager @ NFDI4Culture