@butonic, here's what I'm thinking: I currently have mimetype detection deciding what type of \OC\Search\Result to return (either File or Folder)--why don't I add two more \OC\Search\Result's, one for Audio and another for Image, and add them to the mimetype detection code. That way, search will still know in the backend what type of Result they are and the frontend will see their 'type' property accordingly. 

Here's another option: I create entirely new providers for Images and Audio, that return a list of OC\Search\Result\Image and OC\Search\Result\Audio respectively. This is more effective because in the future a user could check a 'Search only for audio' box and results would be pulled straight from the correct provider; otherwise, we have to start adding more and more filtering code to the File provider as we have more result types.