Thanks for the question!
There is a lot of positivity regarding changes to the current travel and public health guidelines. To keep up to date as you try to make plans, we'd suggest keeping an eye on our own Traveler's Health Page
for all official resources.
Regarding indoor dining and pubs, the government website on reopening of hospitality
advises that non-EU DCC visitors will require physical proof of their vaccination status, so this will be the actual CDC vaccination card with the relevant information. A photo will not be adequate, you will also need proof of US residency such as your passport or driving license.
I hope this helps, where are you planning on visiting during your time with us?