If you need to send uncompressed images send it as a “document” rather than an image. You won’t get the preview but it’ll be the same file as on your phone.

Competitive programming.

Usually multiple algorithmic problems that are released to public at the same time and the fastest people to submit a correct solution get more points.

A fun one I still like to participate in is advent of code, which is a yearly christmas themed one with two problems released a day during advent.

If you want to seriously compete in competitive programming, you need to learn and memorize different problem types and the solutions to those. A bit like you start learning patterns in chess.

For practicing, the CSES Problem Set is a gold mine for practice problems. Theres also a list of competitive programming books on the site.