not all blobs have a name.  More specifically, only Files will have names, Blobs won't.  If you add a picture from the camera or from the wallpaper app, for example, no name is provided.  We should check if there is no name, and generate a name ourselves.  We should add a localized string, probably on a per-mime-type basis.  So we'd have the string: 'unnamed-attachment-image-jpeg=Photo{{n}}.jpg' or something like that.  We probably want to check with UX on this.