@Kirsten-And-John0
For the guests who do not have a photo: you are well within your rights to message the guest and let them know that you require a clear profile photo as a condition of booking with you. (I am assuming you have this in your house rules. If you do not, maybe add it.)
If the guest does not respond or refuses to provide the requested photo, then contact Airbnb support and let them know what the situation is. In these cases Airbnb support is normally happy to give you a penalty-free cancellation.
I had a conversation with an Airbnb executive who told me there was a reason Airbnb doesn't enforce the profile photo like they used to. Their analytics showed that many guests, when confronted with the requirement to provide a photo before making a reservation, would just abandon the whole process and not make any booking.
Airbnb figured the hosts would rather have the guest make the booking first, and then handle the photo requirement afterwards. Once the guest has invested their money in a reservation, they are more committed to the process and should be willing to comply.
It is really a part of their effort to get more business for the Airbnb hosts.