Technology moves fast! There are two known issues with iOS11 that we are fixing now. In the meantime you can use the following solutions:
- Tap "..." in the share options and select Twitter from the list of apps. (You will need the Twitter app installed for this.)
- If Timehop says it can't access photos and there is no option to turn it on, you can re-install it and grant Photos permissions when you log back in.