Does it fit you
Three yes answers and this viewer is built for exactly that, so open it with whichever one you already have. One no on the number, and the email works the same way from the same screen.

You already have their number, or their email. The camera history the device saved opens with that same line.
Runs in your browser, nothing to install on either phone.
Three yes answers and this viewer is built for exactly that, so open it with whichever one you already have. One no on the number, and the email works the same way from the same screen.
What it does instead is the small part you came for: two live lenses and the history already sitting on the device, side by side in one window.
You type the number or the email, and the screen names the device it matched.
The window opens with the front lens on one side and the back lens on the other, both moving.
You press the history strip, and the frames the device kept earlier load under the two feeds.