Scald File introduces a file provider for the scald module. It also provides a common display for all the files in wysiwyg, atom reference fields and in the library, where the file type icon is shown with the filename, and the filename is a link to the actual file.
Customization of thumbnail
Scald File uses one icon (or thumbnail) per file mime type. It is not a field, thus you can't customize the thumbnail display using Field UI. You can also choose a default image for the thumbnail field, but in that case you don't have customized thumbnail per mime type.