Upload your images, or copy paste the link (e.g. from Google Images), and click create image.
Try it out:
How to customize the template
If you want to customize the design further (e.g. change device type, add your own brand logo, your own background colors or text) - sign up for a new account.
If you want you can share your own grid design as a small design generating website too! Learn more about how to do this here.
If you are looking for beautiful app screenshots of the most famous apps such as e.g. the Netflix mobile app check out Screenlane - they have a wide selection of inspiring app screenshots (and videos).