The `nuxeo-document-preview` element has hard-coded mime-type checks for filtering the preview elements. I don't understand why this is the case because the platform already has a mime-type registry with all the necessary mappings. Maybe the issue is it's not exposed via the REST API?
So, for example, if you upload a PSD file using Firefox from a document creation dialog (not drag and drop), you end up with a mime-type like "application/x-photoshop" which fails to pass the filter for nuxeo-image-viewer.
But I think the broader/more important point is we shouldn't have the mime-type logic on the front-end when it already exists on the back-end.