Bittrex is asking me to scan my ID and send them my photo

However, OP got many answers which would help you. I have been using Bittrex from the beginning of my crypto journey. This was the first exchange for me where I registered. Suddenly they asked to verify the account and disabled withdrawal. So there was no way to skip that. So I complied with their KYC policy by force. So this isn't a scam at all though I do not use Bittrex much. Just holding the account for some shitcoin there. This is a privacy issue rather than a scam issue as long as you are visiting the right URL.

Hope you took the lesson leaving funds on a centralized exchange. Do store your cryptocurrency in a custodial wallet or exchange for a long time. Otherwise, you will face the same issue in the near future. Other users should take a lesson as well from here.