Save should use desired sample format fixes #1028

        filename_base = str(int(time.time() * 1000))

        for i, filedata in enumerate(images):

            filename = filename_base + ("" if len(images) == 1 else "-" + str(i + 1)) + ".png"

            filename = filename_base + ("" if len(images) == 1 else "-" + str(i + 1)) + f".{opts.samples_format}"

            filepath = os.path.join(opts.outdir_save, filename)

            if filedata.startswith("data:image/png;base64,"):