I requested more photos of the apartment from the host. The host requested my email, which I provided since i'm the one requesting more information. Airbnb posted "email hidden by Airbnb". Does this mean the host didn't receive my email?
Until a reservation is confirmed Airbnb removes phone numbers and email addresses from the messages sent on the Airbnb system. So, yes it means that the host can't see what your email address is.
All you can do is ask the host to upload the extra photos to the Airbnb page for the listing.