Can I save an image in 1Password and later retrieve that image without an internet connection?

I'd like to add to that also. My case most of the time with the documents is either a traveling or some government building for example. In the first case the internet is quite limited and not always present. For the buildings is the same, there is no always a wifi or a good connection.

also your site says :)

With a 1Password membership, you can access all your passwords and other items from any of your devices, whether you’re online or offline. Apps for Mac, iOS, Windows, Android, and Linux are all included.