We know a little about this charming portrait, which manages to be both formal and casual in the same moment. It was, we know, taken at Mr William Harding's studio at Wanganui on March 17, 1888.
We know the sitters' names too and can, perhaps, guess a little at their social station. Mr Greem, who wears the trilby, loose shirt and trousers of a working man, is on the left.
Mr Collie, who sits to the right, is in the bowler, waistcoat and tie of a middle-class fellow. Mr Greem has a bum's fluff moustache and seems to raise an eyebrow ever so slightly.
Mr Collie, who wears first-rate mutton-chops (neatly trimmed), stares confidently at the camera, a pipe clenched in mouth. But it is what our eyes can't tell us that tantalises a century or more after these two handsome devils visited Mr Harding's studio.
What you can't help wondering, as you notice Mr Greem's and Mr Collie's knees slightly touching, is what did these men mean to each other? They are friends, certainly - if, oddly for the period, from different social classes - but were they lovers too?
For Dunedin academic Dr Chris Brickell, the picture and its inherent ambiguity are a clever thematic launching pad for his first book Mates & Lovers, a richly illustrated, lively and thoroughly absorbing history of gay New Zealand, published by Random House next week.
Brickell, a senior lecturer in gender studies at the University of Otago, discovered the portrait of Mr Greem and Mr Collie several years ago among the collections at the Alexander Turnbull Library.
It has intrigued him since and, though he's not arguing the men definitely had a sexual relationship, it has provided him with a convincing starting point for meditating on the complexity of men's relationships from the colonial period on, what they meant and how they've changed.
The photograph, the book's cover image, also underlines the title, which he admits with a giggle, is ever-so-slightly provocative. "The title is something I chose, not the publisher.
It came, in large part, out of thinking around the early material in the book, and thinking about where the boundaries between these things lie; the boundaries between mateship, friendship and erotic relationships ... and about how those things have changed somewhat over time.
"It also allowed me, by looking at those tensions, to look back at the past and say, firstly, are there aspects to male mateship and relationships that we haven't looked at?
It also allows me not to have to box men in the past into our current understandings of homosexuality and heterosexuality ... I don't have to say 'were these men mates or were they lovers?' but instead say 'what does it mean to talk about them in that way?' Can we see aspects of men's relationships, generally, that were perhaps sometimes more affectionate than we might imagine close relationships to be now?"
Brickell's book, then, is as much a history of the shifting meanings and sometimes uncertain nature of masculinity as it is a history of New Zealand men's same-sex desires from colonial times to the birth of the gay liberation movement of the 1970s.
It wouldn't be altogether unexpected if Mr Greem and Mr Collie were more than just friends. It turns out the Man Alone wasn't such a solitary character after all.
The mythical individual who cleared bush, dug gum, panned for gold and broke in land for farming - as immortalised in John Mulgan's novel Man Alone - presents as an altogether more sociable and sexual fellow in the pages of Mates & Lovers.
Among the book's revelations, is that the circumstances of colonial life - single men thrown together, sometimes in shared beds, in cheap hotels and work camps - coupled with the surprisingly relaxed social codes of the time, meant it was easy for mateship to metamorphose into erotic relationships.
For much of the 19th century there were only two types of illegal sex between men: forcible assault and sodomy, which left plenty of room for those with an imagination. However, his extensive research into court records from the period suggests there were only a handful of convictions each year for sodomy, though colonial administrators fretted that sexual "vice" was widespread.
"I think in a sense that the 'Man Alone' view has been accompanied by an assumption that maybe there couldn't be an erotic component to it sometimes. Of course I'm not saying that there was all the time, but that within male culture there were those possibilities.
The Man Alone figure was certainly a figure, but ... there is another side to the colonial past that perhaps we haven't looked at closely. Whether people agree with it or not, (Mates & Lovers) certainly is another treatment."
Brickell's text has abundant stories drawn from court files suggesting that, while sex between men was a common part of frontier life for some, other men found themselves the subject of unwanted attention - sometimes with amusing effect for modern sensibilities. One Albert Smith, for example, sublet his bed (a not uncommon practice when beds were limited) to a fellow miner, a Terence Eggleton, at the Shamrock Hotel in Wetherstons Gully in Central Otago, one night in 1862.
The pair had not long been in bed when Smith took his opportunity, flipped Eggleton over and, according to Eggleton, "put his private parts to my backside". As Brickell drily reports, Eggleton primly testified in court that he "found it was time to leave". The concerns of the authorities were eventually formalised in a new Criminal Code Act in 1893, making all sex between men illegal, while the jailing of Oscar Wilde in Britain also hardened attitudes in New Zealand, particularly in the press.
In the first half of the 20th century the medical profession - notably the developing field of psychiatry - was instrumental too in codifying same-sex desires medically, and casting it as some sort of treatable illness of the mind.
It is no wonder then that homosexuality, while never something that was, well, out, disappeared further into the shadows.
It wasn't until a century after the events at Wetherstons Gully that the full weight of law was brought to bear. It was only in the late 1950s and early 1960s - by which time a strong, if hidden, gay subculture had quietly developed away from the view of wider society - that police began actively harassing and arresting gay men.
It seems the activities of homosexuals became more closely scrutinised as a wider moral panic over youth running wild exercised polite society, politicians and the press (notably that scurrilous, prurient rag, Truth). "Looking at the statistics you really see the convictions for total sexual offending went up at that point.
Of course the vast bulk of that total was relationships between young adult men and teenage girls, and the overall rise was very much on the back of that moral panic.
It would make sense that the policing of homosexuality got caught up in that, although in a way it seems to have been less a police preoccupation than heterosexual improprieties." In one of the paradoxes that punctate New Zealand's gay history, this rise in convictions for homosexual acts began after the penalties for sex between men had actually been reduced in the early 1950s.
"That period is so fascinating because there are all of those contradictions," Brickell says. However the first moves, which began in 1960s, to have same-sex acts legalised (something that didn't transpire until 1986) happened in part because of the contentious policing and the resultant spike in prosecutions that began in the late 1950s.
It is in revisiting the circumstances surrounding a conviction some 30 years before this that Mates & Lovers courts controversy.
In a now-famous case, Norris Davey - who later lived and wrote under the name Frank Sargeson - was convicted of sexual assault in 1929.
In his definitive biography of Sargeson, the late historian Michael King says, based on an interview with Sargeson's sister, that both Sargeson and artist Leonard Hollobon were caught in a sex act by detectives in the latter's boarding-house room.
As King tells the story, police considered Hollobon to be a "corrupter of youth" and had put him under surveillance leading to the pair's arrest.
The story - as King relates it - suggests New Zealand police, like their counterparts in Canada and Britain, were actively targeting homosexual men. However, Brickell says, the court records for the period indicate there was very little systematic police surveillance. So how to reconcile the Sargeson story?
In fact, court records reveal an altogether different story about Sargeson and Hollobon's arrest, one which better fits the fact police were not, at that time, methodically watching and arresting men for same-sex acts. According to the Hollobon trial file, the artist was actually the victim of blackmail by one of his one-night stands, something he rather surprisingly reported to police - including the reasons why. He mentioned three men in his written statement, but the full name and address of just one: Sargeson, who was then arrested and sent to trial.
Brickell's research also shows King was wrong in suggesting Sargeson may have suffered guilt and depression after claiming to being a victim of Hollobon's advances - thereby setting up Hollobon. In fact Hollobon was the betrayer, shopping Sargeson to the police.
It's a fascinating revision of a defining moment in Sargeson's life, and is an exciting discovery for Brickell. "You can imagine that I was jumping up and down in the archives but trying to preserve some kind of decorum as I was reading the Hollobon trial file.
I think it's useful to be able to retell that story, because it fitted better into the pattern [of policing at the time]."
Identity is at the core of Brickell's book. The text moves chronologically from the colonial period, to the tightening social climate in the early 20th century, to the emergence of "queer" culture in 1930s and 1940s, and the rise of a reformist movement in the 1960s, and the gay liberation movement in the following decade.
However, it ends in roughly 1980, leaving the decades since - which saw law reform and civil union - to a short epilogue and an even shorter afterword. "The reason I've done that is because ... the arranging theme of the book is identity," Brickell says.
"I've stopped once the modern gay identity had more or less come to be formed." He ends, too, when (possibly) the most interesting part of the story has been told, he concedes.
However, when Brickell, 36 and gay, began researching the book three-and-a-half years ago, he wasn't sure exactly how much of the story he'd be able to tell because the history of gay New Zealand is, inherently, a hidden one.
The research did involve speaking to a number of men - one as old as 90 - but it was also part archaeological dig. "The view had been, with the New Zealand history, that there really wasn't an easy way in and there certainly hadn't been an awful lot published for the period before the 1960s.
But it did mean, when I chanced across older chaps who were interested in speaking and who sometimes brought out their photos, that there was just this amazing moment of revelation that there was a life there, when we thought there maybe wasn't before gay liberation.
"But these photos and the stories came out and it started to become clear that there was a whole kind of subculture, certainly by the 1930s and 1940s, that had been there but had been so under the radar I guess that it hadn't been noticed."
Brickell's own interviewing (along with interviews culled from a Wellington project in the early 1990s which had never been published) were key to understanding what was hidden, including the interview with 90-year-old Christchurch man, Derrick Hancock, who revealed his erotic life behind barbed wire as a conscientious objector during World War II.
"As far as I can tell, there is no other way into kind of discovering the homoerotic life of somewhere like that - other than to have someone who was there and is willing to talk. There would be no way I could tell that story at all, because there is no other point of access to it. It's incredibly important being able to talk to people about those kinds of things."
Also crucial to understanding the period before the 1960s were two literary figures, Eric McCormick and James Courage - whose novel A Way Of Life, about a gay love affair, was declared indecent in 1961. Courage's archives were locked up until 2005, so the very minute they became unrestricted Brickell was in there and poring through his diaries.
"What struck me most about Courage was, especially once he got a little bit older, he held back so little and he expressed himself so freely to his diary and talked about his desires in such eloquent prose and I really felt that sense of getting to know him quite well through reading his diaries. So there was a sense of something that happened been out of view, had just come into view."
Brickell's book is no bleak history. Indeed, despite the long criminality of gay sex, the persecutions of police and the misguided notions of the medical profession, Mates & Lovers reveals a lot of fun was had - as many of the vivid and entertaining period photos reveal.
"I, in no way, wanted to negate all the horrible things that happened and certainly life was no bed of roses at all. But I think from our viewpoint it's become to easy too see the period prior to law reform or liberation as simply a dark, black hole in which any kind of fulfilment and any kind of social bonds were completely impossible."
The most rewarding thing, he says, was to see beyond that and to find, for example, that gay men who are now in their 60s and 70s did have, and enjoyed, a social world, even if it had been hidden or forgotten.
"So there is something quite satisfying to celebrate those guys' tenacity and also their ability to create something that managed to mitigate the worse excesses of what was going on, and transcend it, if not completely.
"In a sense, one part of the joy of this is being able to render a much more complex picture of human creativity, resilience and enjoyment."
* Mates & Lovers (Random House, $49.99) is released on July 4. Chris Brickell will read from and discuss his book at the Auckland Art Gallery on August 3, at 3pm.