private IMAGE_TYPE getImageTypeByMime(String mimeType) {
        if (!TextUtils.isEmpty(mimeType)) {
            if ("image/gif".equals(mimeType)) {
                return IMAGE_TYPE.GIF;
            } else if ("image/png".equals(mimeType)) {
                return IMAGE_TYPE.PNG;
            } else {
                return IMAGE_TYPE.JPG;
            }
        }
        return IMAGE_TYPE.PNG;
    }
get mime type displayed in database.

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