Family Visa freelance/self employed support spouse question

Dear Forum members,
Thank you in advance for reading and for any information or thoughts you may have in response to my question.
I am a British Citizen currently living in New York with my wife and son. My son also has a British passport.
The three of us want to move back to the UK, initially to live in my father's house in Norwich, then eventually to our own place.
My wife only has a US passport so I believe that she will need a family visa before eventually applying for citizenship. She and I are both self employed freelance photographers in the US earning between £25,000 and £50,000 (in dollars though) per year each. We also each currently have savings of over £30,000. However, as freelance photographers we would not be coming to a job offer in the UK but would start looking for work once we arrive.
So what would be the best way for us to prove our financial security for the family visa application ?? Would we show past US income or would we be depending on proving the savings ? I haven't yet found good advice on our best course of action.
Thank you very much for your help.
Joshua Bright.

You won’t be able to qualify to sponsor your wife until you have a FULL U.K. tax year of accounts audited for the application, which would mean separating your family for a couple of years.

The “easiest” way to qualify will be to show six months of savings that has stayed above £62,500. 

Hoping you are able to do the savings route. It’s really your only option. 

Thank you KFdancer.
So is it true that in no circumstances will our proof of earnings in the US be useful?
I had not heard of the £62,500 figure. Can I ask where you got that from?
Also, do you know if that saving can be shared between the two of us or must I alone have that amount?

Thank you KFdancer.
So is it true that in no circumstances will our proof of earnings in the US be useful?
I had not heard of the £62,500 figure. Can I ask where you got that from?
Also, do you know if that saving can be shared between the two of us or must I alone have that amount?

It's all in here.https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1039148/1.7_-_Financial_requirement.pdf

It can belong to either or both of you but not anyone else. Gifts of cash are acceptable but must be genuine with no intention to repay. And the money would still need to be held for the full 6 months.

Welcome!