outgoing.go
func (op *OutgoingPhoto) querystring() querystring {
	toReturn := map[string]string(op.getBaseQueryString())

	if op.Caption != "" {
		toReturn["caption"] = op.Caption
	}

	return querystring(toReturn)
}
func (op *OutgoingPhoto) querystring() querystring {
	toReturn := map[string]string(op.getBaseQueryString())

	if op.Caption != "" {
		toReturn["caption"] = op.Caption
	}

	return querystring(toReturn)
}
// querystring implements querystringer to represent the photo.