How to re-center/re-size my iCloud memoji image?

I created a memoji to share in Messages and use for my iCloud "photo". To do so, on my iPhone, I went to Settings->Messages->Share Name and Photo->Edit->Customize->Contact Photo.

Somewhere in that process, it gave me the option to resize my image. I chose a kind of "full body" view, rather than expanding the image to focus more on the memoji face.

Now, I want to expand that image. However, when I go through those same steps, it's giving me options to change the memoji (or the poster). I don't see anything allowing me to pinch or zoom the memoji within the poster.

Do I have to go through the process and start all over? Or, is there something I'm missing that would allow me to simply expand the memoji portion to fit more of the circle background?