Aerial shots of Kranji's Royal Navy Wireless Station, where Japanese Navy codes were cracked by the British before World War II, and a collection of Singapore postcards from the 1960s to 1980s, are among the new images which have been uploaded to a local history website.
Contributions to the One Historical Map portal, managed by the Singapore Land Authority (SLA), have come from around the world.
The shots of the Kranji wireless station come from Briton Lucy Childs, 47, whose father worked there in the early 1970s.
Ms Childs, an artist, started a Flickr group called "Singapore, Pre-1975" five years ago to get former residents of the Republic to contribute historical photographs "so these valuable records would not be left to rot in family photo albums". She is encouraging members to share their content on One Historical Map, which she believes is a good central historical resource.
"The photos taken by the locals and temporary residents over the years stand as a wonderful reminder of the beautiful island and its journey," she said. "It could help younger generations see that journey and appreciate its heritage."
Briton and Singapore permanent resident Michael Peter Fong, 52, a graphic designer who lived here from 1969 to 2000 and now resides in Scotland, submitted his mother's postcards as he "felt the need to share those times and memories with others".
Since its launch in December, One Historical Map has attracted more than 20,000 views.
More than 650 photographs have been contributed and geotagged by members of the public as well as SLA and the National Heritage Board (NHB).
Mr Fong's old postcards help to chronicle the evolution of the island's landscapes at key landmarks such as Empress Place, The National Theatre and Sultan Mosque. He said: "I was fortunate enough to see Singapore as a post-colonial city, with a quaint village atmosphere, transform into one of the most modern, dynamic cities in the world.
"These are all now memories, but they can be shared."
Also accessible on mobile devices and tablets, the service and app allow users to compare what different parts of the country looked like in 1966, 1975, 1984, 1995, 2007 and the present day.
A team of geospatial application specialists from SLA had stitched together 4,600 old maps.
NHB assistant chief executive of policy and community Alvin Tan, said the board is thankful to contributors who are helping to bring these maps to life.
He added: "We are especially heartened by contributions from individuals who continue to regard themselves as friends and fans of Singapore even though they are living beyond our shores."