How to create a backend for storing photos sent from a smartphone?

Question

PHP

Good evening everyone. I am developing for android (native sdk, java) and I wanted to write something for the backend to broaden my horizons (I have no experience in the web at all). I set myself the following task:
I have a ready-made application that can take pictures and send pictures with comments to the Firebase storage. I want to write my own backend from scratch to send photos and comments to a remote server/my computer. The server is accessed via json api. In the choice of technologies, I have so far settled on php and MySQL. I am interested in the following:
1) what languages ​​and technologies will optimally help me solve my problem?
2) what theoretical knowledge is needed to solve the problem?
3) tell me some good tutorials that will allow me to quickly deal with php and MySQL. Or tutorials where such backends are made.

Answer 1

You write in java, write backend in java. The baggage of knowledge will be incomprehensible. Create an http server on some port and write data to a file.