Image copyright Adam Schemm Image caption Norbert Schemm, 87, was surrounded by his loved ones during his final days

Why would a picture of a dying grandfather having a final drink resonate with so many strangers around the world?

All Norbert Schemm, 87, of Appleton, Wisconsin, wanted in his final moments was his loved ones beside him while he sipped a beer.

Together his family talked, laughed and reminisced before taking an image which Mr Schemm's son Tom shared with the family Whatsapp group.

But hours later when Mr Schemm died and his grandson Adam posted the photo on social media, the entire family was overwhelmed by the number of strangers who took comfort in that last picture.

It has already had more than 4,000 comments, 30,000 retweets and 317,000 favourites on Twitter alone and has turned up on Reddit and other social platforms.

Adam said: "My grandpa had been relatively healthy over the course of his life but it was on the Sunday last week while he was in hospital that they realised it would be the end. He called his grandchildren to tell us on the Monday. We took the picture Tuesday night and then he died from stage four colon cancer on Wednesday."

"My dad told us that grandpa had wanted a beer and now when I look at that picture it gives me solace.

"I can tell my grandpa is smiling. He's doing what he wanted to do - it was an impromptu moment."

Adam said he was hesitant to post the picture on social media first because of the bittersweet context but decided to go ahead because it was just a beautiful moment.

"It's actually helped us with our grief. It's comforting to see that my grandparents and their children were all together in his final moments."

He said the family had been tracking to see how far the image had travelled and they loved that so many people were sharing it.

"It seems to have tapped into a sense of community and clearly is a moment lots of people relate to. The comments have been so kind and we've seen pictures of people toasting bottles of beer in his honour. I thought people I knew might want to see it and respond but had no idea just how many people it seems to have helped."

Ben Riggs, of Indianapolis, was among the strangers who felt prompted to respond to the image on Twitter. He posted a photo of his own grandfather Leon Riggs, 86, enjoying a final cigar and beer too.

Ben told the BBC he spotted the image on his Twitter feed and it reminded him of his grandfather's final request when he died in 2015.

"I don't delete the pictures on my phone. I returned to it and I felt compelled to reply and share my own photo. It brought me back and to see someone else experience that final bit of happiness before death was a good feeling."

Ben said his grandfather had had Alzheimer's and his memory would come in waves but towards the end, he and his dad felt it important to fulfil his grandfather's dying wish.

"While death never comes at the right time, I think it's important to always try and find the silver lining."

Ben said the evening his grandfather died, he, his brothers and his father got together to mark the passing and celebrate the life. They took another family photo. Tragically, Ben's father Mike died unexpectedly the next day from heart failure. He says both of these final pictures have brought him much comfort.

Image copyright Ben Riggs Image caption Ben Riggs lost both his father and grandfather within the space of 48 hours but finds comfort that he and his brothers have a photo taken with their dad hours before he died.

Brigid Reilly, of Philadelphia, also responded to Adam's original tweet with an image of her grandmother Theresa Meehan who passed away in October this year from heart and kidney failure at the age of 84.

She told the BBC: "My grandmother got put on hospice care so we knew she would be passing soon.

"Towards the end my family wanted to bring her her favourite things which included sushi, Frank Sinatra's music, all of us together, and her drink of choice which was Baileys. As she got closer to the end she requested we all do a final shot together."

Image copyright Meehan family Image caption Theresa Meehan wanted to drink Baileys liquor with her family as she came to the end of her life

Brigid said that the image was printed out and shown at her grandmother's funeral.

"We made a video commemorating her life and included it in that. But mostly I just cherish it personally. I think I'm really lucky to have had those final moments with her."

But what is it about the picture that has led to hundreds of thousands of people reacting to it?

Why did the photo resonate?

Ann Neumann, author of The Good Death, says: "It has resonated because it is something we all long for. Because the image gives us a chance to think of our own loved ones and to join the Schemm family in this most profound moment.

"But it also gives us a chance to grieve with them; in doing so we can think of our own loved ones, elderly, ill, dying and dead."

She said the image captures what everyone would want on their last night - to be surrounded by loved ones.

She adds: "Few of us know the time of our death or have the presence of mind to mark it in this way. We live far-flung lives, with our family members residing in other states or countries. There are millions of stories of adult children missing their parents' death because of distance.

"There are millions of stories of a dying parent being unconscious the last days of their lives. Missing the chance to say goodbye is a great human fear. The opportunity to share this rare and beautiful last gathering resonates because it is one version of an ideal death.

"If there is a lesson in this photo, it is to mark and hold dear all the time we have with those we love. Hoist a beer, hold hands, share stories. Time is finite."

Why do we share deathbed photos?

Dr Kenneth J Doka, senior bereavement counsellor at the Hospice Foundation of America and past chairman of the International Work Group on Death, Dying and Bereavement (IWG) Mission, says there is no specific right thing to say or do when it comes to the final moments of a life.

"I think the key thing is to listen and when someone is dying to let them share their moment of significance."

He described the photo as a delightful image and added he was unsurprised that Adam posted what could have been thought of as a private moment on social media.

"We have always used technology to deal with dying and death. The Ancient Egyptians used pyramids; what we are doing now is adapting our rituals to the technology that is available."

Adam says his grandpa would have found the attention remarkable.

"I don't think he would have minded. He would have got a laugh out of it.

"I think the biggest lesson to be learned and what I believe my grandfather would say is to 'be kind, love each other, and that family matters'.