An old floppy disk found in state archives has revealed the faces of some of the 45 people executed at the Adelaide Gaol, Natural Resources Department tourism sites manager Gary Joyce says.

"These were people who were jailed for crimes including murder and theft, and some of them were executed at the jail," Mr Joyce said.

One of the condemned is 23-year-old Albert William Bonfield who was hung in 1904, after being found guilty of murdering his girlfriend with a revolver in a fit of jealous rage.

Prior to his execution Bonfield told the officiating minister he deserved to die for his crimes and that he would meet his sweetheart in Heaven.

The shots are part of an exhibition at the now-closed jail starting on Sunday which also includes letters of confessions and historic newspaper articles.

The jail built in 1841 housed more than 300,000 inmates before it closed its doors in 1988 and is one of the state's oldest remaining public buildings.

Australian Associated Press