An eight-year project to digitise 6,000 photos has provided an insight into how Ipswich has changed over the years.
Tony Marsden, vice-chairman of the society, said the "dynamic" collection documented a changing landscape.
"There's a certain poignancy to the collection. The photos evoke another world," he said.
"Ipswich has got a very colourful and varied history."
Several of the modern day photos have been taken to provide a comparison of how certain areas of the town have been transformed. The Electric House is shown above in 1977, when it was home to Radio Orwell and overlooked celebrations for the Queen's Silver Jubilee visit to Ipswich.
Norman Foster's Willis building is one of the modern architectural highlights of Ipswich. The Ipswich Society's photos show how the site used to house a shoe shop.
Mr Marsden said some of the comparison photos illustrated change is not always for the best.
"When you think about what's replaced some of the buildings, that's when the guilt creeps in," he said. "There are several regrets about what has happened, especially during the '60s."
Photos of the waterfront, which is still being developed, show how the area's industrial heart has been replaced by housing and retail outlets.
Mr Marsden said he recently gave a talk on the archive and was "astonished" by how it prompted people's memories, and the stories which followed.
He said he hoped people would find the archive a "tremendous diversion".
"I find myself looking at them and an hour later my coffee has gone cold," he said.
His favourite of the collection is the photo showing the billboards on the corner of Falcon Street, with the women in short skirts and the vehicles helping to provide an evocative snapshot of the period.
"That is an absolute masterpiece," he said.
"You've got beer, fags and gambling. It's such a telling shot of the 1960s, it's brilliant."