Flask app which enables users to push images from their phones to a single gallery page running on a beamer.
Thanks to @bixel and @MaxNoe.

1. Create a new python 3 virtual environment and pip install -r requirements.txt.
2. python start.py to start the debug server at localhost:5000.
3. localhost:5000 is the client page where you can push a photo to the gallery page.
4. localhost:5000/gallery is the gallery page where the pushed images are shown, supposed to be running only once on a beamer with a fixed page size.
5. Put a placeholder picture in ~/Pictures/wedding/_placeholder.jpg, for an empty database.
6. Posted pictures are saved at ~/Pictures/wedding/ with a timestamp and at full resolution.
7. Center image container show the last posted image with its comment, if available. 4 surrounding image container show randomly picked images from the database - updated every 15 secs.
8. Posting images available if devices are in the same WiFi and directing to the server IP adress with port 5000, also working without internet connection.