The ACO format is a special format used only in Photoshop, so there's no reason to convert one to any other format.
Ọkpụkpọ ACO bụ usoro pụrụ iche a na-eji na Photoshop, n'ihi ya, ọ dịghị ihe kpatara iji tọghata faịlụ ACO na usoro ọ bụla.