It looks like the content repository assumes that "images" will be stored as subtypes of the image content type. What exactly counts as an image is not defined. SVG files can be used to create images, but are XML.
File storage currently stores every file uploaded as a file_storage_object which is a subtype of content_revision.
Is there a signifigance to using hte image content type? It stores the height and width of the image in the images table. I don't see that file storage uses this, but a package that created a compound object type or needed to construct an img html tag would need it. Because images can be stored as a CLOB in the database, no simple operation can get the information after it is uploaded.
So, should file storage switch to storing images as image content type?
This will not affect the user interface of file-storage one bit. It just affects the pl/sql api that creates a new file storage file.
The reason I ran into this was when I converted file-add to use ad_form and tried to use cr_import_content which forces mime types for JPG and GIF into an image content type.