Image copyright Brent Walker

When recovering meth addict Brent Walker posted before-and-after photos of him and his wife on Facebook, he hoped to inspire change in old friends.

But when, 10 days later, they had been shared almost 200,000 times. Brent, of Tennessee, was pleasantly surprised.

In the "before" photo, Brent and Ashley are at the height of their addiction. The "after" one was shot last month, as they celebrated three drug-free years.

He wrote: "I hope... my transformation can encourage an addict somewhere."

"It is possible to recover," he added, underneath the pictures.

Brent told BBC News: "It [the photo] was just for my family and friends, some of whom are recovering addicts. The next day, my phone was blowing up.

"I want to tell people they don't have to live like this. We are living proof."

Brent and Ashley met in 2010, when he started supplying her with drugs.

Image copyright Ashley Walker Image caption Ashley met Brent when he started supplying her with drugs in 2010

"Meth messes with your brain, it makes you paranoid, it makes you lose your memory and hallucinate," he said. "I couldn't eat. I didn't sleep for days on end."

The couple lost custody of the five children they had between them. Ashley went into rehab but relapsed, and Brent was in and out of prison on dealing and possession charges.

Image copyright Brent Walker Image caption Brent Walker at the height of his addiction

And then, they "decided they didn't want this anymore".

"We decided to go to church and we got rid of anything that was associated with the drug life," Brent said. "That included cutting people off and getting new friends.

"One of the biggest problems for recovering addicts is remembering the 'good times' with friends and falling back into it, so we had to stop seeing those people."

Image copyright Brent Walker Image caption The couple on holiday in Florida last month

They knew being drug free would be a long and difficult journey.

And they decided the way to do it was to set small milestones.

The first was to get married after 30 days of being sober.

The second was to find a place to live, as they had been sleeping on the floor of their friend's apartment.

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The third was to buy a car.

Despite their addiction, they had been able to hold down jobs, Brent at a carwash and Ashley at a factory, but they would spend all their money on drugs.

"We would walk long distances to the grocery story, our clothes were in garbage bags and we walked to work," Brent said.

Now, the pair have set themselves more goals to achieve, including improving their credit score so they can put a deposit down on a house, and taking steps to regain custody of Ashley's children.

Image copyright Ashley Walker

Brent said: "It is tough, and it takes time to get healthy, but the end result is amazing.

"My message to anyone struggling with addiction is anything is possible.

"The motto I live by now is life is an adventure to enjoy, not a problem to be solved."

On Facebook the couple's post has received over 18,000 comments, some from other recovering addicts.

One Facebook user called Cynthia wrote: "They deserve a medal because it's a struggle every day when you're trying to get clean.

"Getting off the drugs is only the beginning, ex-drug users have to learn how to live again sober, they have to have a plan. Brent and Ashley thanks for sharing that."

Another, Stephanie, commented: "Great job, I'm sober five years. It takes a lot to quit, you have to give up tons of people, friends and family etc not to mention the sickness you have to deal with. You have to work for it. Good job on it, y'all look amazing."

More on the US drug crisis

Media playback is unsupported on your device Media caption On America's trail of destruction

If you or someone you know needs help with addiction, in the US you can call the National Drug helpline on 1-844-289-0879, or visit their site.

If you are in the UK you can find help and support via the BBC Action Line.