Как сделать галерею в kivy?

Я набросал пример галереи, я думаю, это то, что вы хотите.

from kivymd.app import MDApp

from kivy.metrics import dp
from kivy.lang.builder import Builder
from kivy.uix.boxlayout import BoxLayout

import os

KV = """
<ImageButton@ButtonBehavior+FitImage>

<ImageManager>
    path: ""
    orientation: "vertical"
    size_hint_y: None
    height: root.height
    padding: dp(10)

    ImageButton:
        source: root.path
        
BoxLayout:
    RecycleView:
        id: rv
        key_viewclass: "viewclass"
        RecycleGridLayout:
            padding: dp(2)
            cols: 3
            default_size: None, dp(48)
            default_size_hint: 1, None
            size_hint_y: None
            height: self.minimum_height
"""


class ImageManager(BoxLayout):
    pass


class GalleryApp(MDApp):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)

        self.manager_list = []
        self.dir = os.getcwd()
        self.available_image_format = ['.png', '.jpg', '.jpeg', '.bmp']  # etc

    def build(self):
        return Builder.load_string(KV)

    def on_start(self):
        self.load_images()

    def load_images(self):
        if not self.manager_list:
            for image in os.listdir(self.dir):
                target_filename, target_file_extension = os.path.splitext(image)
                if target_file_extension in self.available_image_format:
                    path_to_image = os.path.join(self.dir, image)
                    self.manager_list.append(
                        {
                            "viewclass": "ImageManager",
                            "path": path_to_image,
                            "height": dp(200),
                        }
                    )
            self.root.ids.rv.data = self.manager_list


GalleryApp().run()