They are a stark collection of powerful self portraits of a Scottish photographer in the grip of drug addiction.

Now Graham MacIndoe's 25 images of a torturous six year period of heroin and crack cocaine addition are to be displayed by the National Galleries of Scotland.

Coming Clean, a series of haunting images by the New York-based photographer, will be shown at the Scottish National Portrait Gallery from April 8 in a free exhibition.

MacIndoe studied painting at Edinburgh College of Art and received a Masters degree in photography at the Royal College of Art in London, before moving to New York in 1992 where he later pursued a career as a professional photographer.

His work began to appear in some of the world’s leading publications - however, he began to use alcohol and drugs and his heroin habit "gradually overtook everything that once mattered."

MacIndoe said: "It is a great honour to have the first showing of this body of work at the Scottish National Portrait Gallery.

"Although the images were taken during a difficult time, I am grateful to have made it through that period and hope this series shows that recovery is possible even from the depths of serious addiction.

"I never anticipated that these photographs would find a place in the national collection, so I’m especially excited for the opportunity to exhibit them in the city where I first discovered photography".

MacIndoe has now been free of drug use for seven years.

He thanks a prison rehab program, what he describes as “a compassionate judge” and the support of his partner Susan Stellin, a reporter with whom he co-wrote Chancers: Addiction, Prison, Recovery, Love: One Couple's Memoir, published by Random House last year.

The period of addiction culminated in an arrest for drug possession and a four-month incarceration in New York’s Riker’s Island prison, followed by five months in an immigration detention centre.

MacIndoe is now a working photographer and as adjunct professor of photography at Parsons The New School in New York City, while he and Stellin were awarded a 2014 Alicia Patterson Foundation Fellowship for a project about deportation.

As well as being represented in the National Galleries of Scotland collection, his photographs also reside in the collections of The New York Public Library, The British Council, The V&A Museum, The Museum of Fine Arts, St Petersburg, Florida and The National Media Museum, Bradford.

The photographer said he hoped to avoid glamorising what had become "a solitary existence, the monotonous repetition of an addict's daily life. I turned the camera on myself because I wanted to photograph addiction from the inside – a perspective most people never see".

Almost all the photographs are set within the confines of his flat in Brooklyn, with MacIndoe as the sole subject.

Annie Lyden, International Photography Curator at the Scottish National Portrait Gallery, said: "These photographs offer a rare insight into a very real aspect of the human condition. Graham’s honesty and courage in documenting this particular moment of his life allows us to see the rawness and isolation of addiction from the inside. The images are powerful and are at times upsetting, but you will not find a more candid and revealing series of self-portraits than Graham MacIndoe’s Coming Clean photographs.”