Broken (error 404) topic display pictures in my koala community

I'm not sure where to post to find someone to help me or a workaround for this, but I'm having an issue on here where the display picture that I used for a couple of topics I posted in my koala community had gone 404. I have tried to ask for help in !support@lemmy.world and sent an e-mail to the admins to try to get the problem fixed, but I had not gotten any response from the admins and I'm beginning to wonder if I need to find someone who may know of a workaround for this.