at least you admitted it that you use other photos. but with such admission, your project is in jeopardy because people or potential investors will not invest on your platform for the fear of screwing them. even if you promise them that you will do your best, your reputation is already tarnished. so i don't think you can proceed your development without having problem in raising your funds. better take down your "borrowed" photos and just be anonymous. and tap private investors to move forward because you can't rely from the crowdsourcing anymore because of the ruined reputation. if you are sincere, one way is to use your own money to develop this project and show to the community that you can deliver your objectives without relying from others.