The change here is when scanning a video for the first time, to get the metadata from the db so that the thumbnail blob is file-backed instead of memory-backed. If the callback is addVideo, it would need to load the metadata from the db, but only in the first-scan case, not when the video has been previously scanned -- where the thumbnail is already file-backed. I like the idea of reducing code by using an existing function as the callback but I don't know if adding logic to addVideo is cleaner -- how would it know whether or not to load the metadata from the db?