She was joined by a panel of judges to select 100 images - from more than 31,000 entries in her Hold Still photography project - launched with the National Portrait Gallery in May.
Kate invited people of all ages across the UK to submit a photo which they had taken during lockdown.
In the six weeks that the project was open it received 31,598 images in total.
Speaking with the judges on a virtual chat, the Duchess of Cambridge said: “I’ve been so overwhelmed by the public’s response to Hold Still.
She added: "The quality of the images has been extraordinary, and the poignancy and the stories behind the images have been equally as moving as well."
Judges on the panel included England’s chief nursing officer Ruth May, director of the National Portrait Gallery Nicholas Cullinan, writer and poet Lemn Sissay and photographer Maryam Wahid.
Commenting on the photos, chief nursing officer Ms May said: “I loved going through this, partly because it gives me a bit of a break from Covid-19 work that we’ve been doing in the NHS, where our NHS and our frontline staff have done an amazing job.”
Kate added: "It’s like a huge roller coaster, isn’t it, of emotions?
“I suppose that’s what everyone has experienced, a reflection of what everyone’s been through at this time.”
She said the images showed “how different and diverse everyone’s experience of Covid-19 has been”, adding: “No one story is the same, everyone’s is unique.
The Hold Still initiative aimed to capture and document “the spirit, the mood, the hopes, the fears and the feelings of the nation” as the UK dealt with the coronavirus outbreak.
Addressing the panel, Ms Wahid highlighted the different religious festivities that were celebrated throughout lockdown which were reflected in the images.
“As a Muslim, there was Ramadan, there was a festival of fasting and then there was a celebration of Eid,” she said.
“For Sikhs there was Vaisakhi, so it was very interesting as there was quite a lot of religious festivities that was happening within lockdown.
“It was absolutely beautiful as well to see so many different volunteers just come together and just help in every single way.
Mr Sissay described how “emotional” the judging process was, adding: “As I studied the portraits in this most public crisis I was drawn into the most private moments.”
The digital exhibition will launch on September 14, with a focus on three themes – helpers and heroes, your new normal and acts of kindness.