I would just stick prematch bets and pic must be posted as soon as bet placed or at least that timeline shows that pic is posted before match started.
Am i being nitpicker by saying that would timelines be better with monday-thursday and friday-sunday? Just for a fact that if you prefer place bets on football, usually not so much action in mon-tue, wed-thursday more and ofc weekends filled with it
@traart has it right. These rules won't work at all.
To me the right way would be not allowing live bets and also the screenshot would need to be posted before the start of the match/any of the matches. I'm tired though so maybe I'm thinking it all wrong