The image shows Mike Bennet, 57, and wife Julie, 50, from Irby in Wirral, holding hands in a Merseyside hospice.
It was taken shortly before Mr Bennet died on Monday from a brain tumour.
Relatives and friends have launched a fundraising campaign to help the couple's three children, Oliver, 13, Hannah, 18 and Luke 21.
It raised thousands in the first 24 hours.
Friend Sue Wright said: "I told her the community would come together to help look after her kids - and she opened her eyes and smiled."
Ms Bennet, a primary school teacher from Sommerville School, died on Saturday at St John's Hospice.
She was diagnosed in May last year with cancer which began in the liver and kidneys and then spread to other organs.
Her husband, a self-employed cabinet maker, had been fighting a brain tumour since 2013 and had been nursed at home by Ms Bennet and the children until his wife became too ill to care for him.
Friend Heather Heaton Gallagher said the "down-to-earth" family are "known to all for their generosity" and "love for life."
"Words cannot express our desperate sadness for such a beautiful family," she said.
"Julie has kept the children in a normal routine whilst dealing with Mike's illness over the past few years.
When Julie became ill, she made it her purpose to create as many memories as a family for the children to hold onto.
"We have set up a JustGiving page and overnight that reached an incredible £15,000, but these three kids need to have a future."