public String getMimeType() {
        if (getImageType() == IMAGE_TYPE.GIF) {
            return "image/gif";
        } else if (getImageType() == IMAGE_TYPE.JPG) {
            return "image/jpeg";
        }
        return "image/jpeg";
    }
get mime type displayed in database.

@return "image/gif" or "image/jpeg".
boxing/src/main/java/com/bilibili/boxing/model/entity/impl/ImageMedia.java