Liverpool's photographic collections have been recognised as being of national and international importance.
The Museums, Libraries and Archives Council has awarded Liverpool Record Office its "designation status" for its extensive archive of pictures.
Organisations with designated collections are seen as looking after the UK's cultural heritage.
Liverpool City Council leader Warren Bradley said the pictures were "hugely important".
"Liverpool has a rich and varied past and can look back on a fascinating story," he said.
"The work of our record office to preserve and catalogue the images which capture this story, and make them available to everyone, is truly priceless.
We place huge importance in looking after our photographic collection - they are the collected memories of Liverpool David Stoker - Records office manager
"I'm very proud that this collection has taken its place among the most culturally significant in the country."
The extensive photographic archives at Liverpool Record Office includes town planning, transport and public health documents.
There are about 180,000 photographs from the late 19th Century onwards.
The collection includes the complete work of Edward Chambre Hardman, which is part owned by the council and part owned by the National Trust.
Lunch was eaten off the Liver Building clock before it was erected
Hardman was one of the most admired portrait and landscape photographers of the 20th Century.
The collection also includes 150,000 of his portrait photographs, of local people and visitors including Ivor Novello and Margot Fonteyn.
Record office Manager David Stoker said: "We place huge importance in looking after our photographic collection - they are the collected memories of Liverpool.
"Our images are used every day to support all kinds of research, publications, exhibitions and the council's work with the media and cultural organisations."
Liverpool Record office attracted more than 43,200 visitors during 2005/06 who consulted nearly 40,000 documents and took up over 40,000 computer and microfilm sessions. source....