Add some pictures and drag them in the right order.
If you have very large pictures, you can edit the PDF options to reduce them in size.
This will give you smaller PDF files e.g. if you want to send them by e-mail.
You can also specify a document title and author in the PDF options.
Once you're done, click "Create PDF".
All the magic happens locally in your web browser on your device.
No data is uploaded. This will save your bandwith and privacy.
If you want to know the technical details, head over to GitHub.