What things I should consider when having table relationships

assuming we have a scenario where a user can participate competitions by uploading picture(s) what would be a better way to create table relationships having the following tables USERS, COMPETITIONS, PARTICIPATED_COMPETITIONS and PICTURES with following relationships

USERS – PARTICIPATED_COMPETITIONS is 1toMany relation

PARTICIPATED_COMPETITIONS – COMPETITIONS 1to1 relation

having this information I would like to know if the options listed below have pros and cons over each other in terms of flexibility performance when creating a relationship with PICTURES table. Which would you consider using and why?

1- I could hold primary keys of user and competition tables as foreign keys in PICTURES table

2- I could just hold PARTICIPATED_COMPETITIONS primary key as a foreign key in PICTURES tables. PARTICIPATED_COMPETITIONS table already has relations to both USERS and COMPETITIONS tables.

Thank you