Refactor postprocessing to use generator to resolve OOM issues

    shared.state.begin(job="extras")

    image_data = []

    image_names = []

    outputs = []

    def get_images(extras_mode, image, image_folder, input_dir):

        if extras_mode == 1:

            for img in image_folder:

                if isinstance(img, Image.Image):

                else:

                    image = Image.open(os.path.abspath(img.name))

                    fn = os.path.splitext(img.orig_name)[0]

            image_data.append(image)

            image_names.append(fn)

                yield image, fn

        elif extras_mode == 2:

            assert not shared.cmd_opts.hide_ui_dir_config, '--hide-ui-dir-config option must be disabled'

            assert input_dir, 'input directory not selected'

                    image = Image.open(filename)

                except Exception:

                    continue

            image_data.append(image)

            image_names.append(filename)

                yield image, filename

        else:

            assert image, 'image not selected'

        image_data.append(image)

        image_names.append(None)

            yield image, None

    if extras_mode == 2 and output_dir != '':

        outpath = output_dir

    infotext = ''

    for image, name in zip(image_data, image_names):

    for image_data, name in get_images(extras_mode, image, image_folder, input_dir):

        image_data: Image.Image

        shared.state.textinfo = name

        parameters, existing_pnginfo = images.read_info_from_image(image)

        parameters, existing_pnginfo = images.read_info_from_image(image_data)

        if parameters:

            existing_pnginfo["parameters"] = parameters

        pp = scripts_postprocessing.PostprocessedImage(image.convert("RGB"))

        pp = scripts_postprocessing.PostprocessedImage(image_data.convert("RGB"))

        scripts.scripts_postproc.run(pp, args)

        if extras_mode != 2 or show_extras_results:

            outputs.append(pp.image)

        image_data.close()

    devices.torch_gc()

    return outputs, ui_common.plaintext_to_html(infotext), ''