"It's because of her that we've got the photograph."

Although it will forever be associated with Windows XP, Bliss was actually the by-product of a love story. It was a regular Friday afternoon in 1996 when photographer Charles O'Rear took the drive through California's wine country to see his then-girlfriend Daphne.

Chuck, as he introduces himself in conversation, has since married Daphne. Bliss, meanwhile, has gone on to become one of the world's most iconic photographs, chosen as the default wallpaper of Microsoft's operating system.

Microsoft/Charles O'Rear

"There's a time of the year in our mid-winter, in January, when we've had rains. The grass is now getting a brilliant green. The storms are still coming through with rain and clouds. While I'm driving this beautiful, winding road to see Daphne, my God, the storm has just gone through, there are some white clouds, boy, I think I'll just get out and make a couple of frames," he says.

Chuck pulled out his medium format Mamiya RZ67 film camera and made Bliss. It wasn't the first time he had attempted to capture the beauty of the hills, though.

"That particular spot, or this area of the wine region, is known for that same thing -- the rolling hills. I have been photographing them for a long time, with film. And yet colours never quite came out the same on Kodachrome 64, the best film you could possibly have. They were never quite green enough."

Today, Bliss looks very different to how it did in the late 1990s. For the curious, you can click here to explore the area.

Charles O'Rear

Despite what many people might think, the original frame of Bliss was completely unaltered and unedited by Chuck when he submitted it to Corbis, the stock photo and image licensing service founded by Bill Gates in 1989.

Corbis -- which means woven basket in Latin -- had maybe 50 photographers on file when Chuck submitted Bliss. Today, there are over 100 million images in the database.

Bliss was purchased by Microsoft for an undisclosed sum. While Chuck can't reveal how much he was paid due to a non-disclosure agreement, it was one of the largest amounts ever paid for a single photograph. He still doesn't know how Microsoft found the photo, whether through keywords or by typing in phrases like "rolling green hills".

"Several years after [Windows XP] came out, an email came to me from one of the engineers, somebody within Microsoft. 'We're just curious about where that photograph was made'," read the email. Chuck continues: "'Most of us in the engineering department think that it was Photoshopped. Some of us think that it was taken not far from Microsoft headquarters in Washington'."

"Sorry guys, you're all wrong," he says. "It's the real deal, it's near where I live, and what you see is what you get. It has not been touched." Microsoft did, however, crop the image for the desktop configuration and pumped up the green of the rolling hill.

Just for fun, Chuck has recreated Bliss entirely in Photoshop, made up of elements from his other photographs. You can see the recreated version here on his Photoshelter page.

Unlike images, operating systems have a use-by date. Microsoft will end support, software updates and security patches for Windows XP on 8 April. So what is the future for Bliss, the photo that remains inevitably tied to the OS?

"I think it's going to be around forever," he says. "When you are 90 years old, somewhere a photograph like Bliss will appear and you will say 'I remember that. When we had computers on our desk, that was on the screen'. Anywhere on this planet right now, if you stop somebody on the street and you show somebody that photograph, they're going to say 'I've seen that somewhere, I recognise that'."

Although there can never be a true indication of how many people have seen Bliss, Chuck estimates it is in the billions. The worldwide spread of Windows XP means that he has seen his own work in some far-flung places.

"The neatest place I have seen was recently, actually it was in the past couple of weeks. An American photographer was allowed to go into North Korea. One of [the photographer's images] was in some power plant, there's a big board where two men were sitting. What's on the screen? Bliss."

"Under the White House there's something called the situation room ... there were maybe 10 or 15 monitors and what was on the monitors? Bliss. I'm sure before they allowed the photographer to come in they had to clean all of the screens, make sure there was no stuff on there we couldn't share with the world."

With a photo as iconic and as well-known as Bliss, there are bound to be people who don't quite share the same exuberance for the image as Chuck does.

"A couple of years ago we got on a ferry out of Townsville [in Queensland, Australia]. There it is on all the monitors. To the woman who was working for the ferry company, I said 'that's my photograph!' and she said 'so what?'"

Despite using a myriad of film cameras during his photographic career, Chuck is now a fierce proponent of digital photography. He carries just one camera with him now -- a Panasonic Lumix LX3. With a 28mm-equivalent lens "which I love", the LX3 is not a new camera by any means, but it does the job for him.

When asked if a modern day high-end digital camera could recreate the look and feel of Bliss, Chuck believes that it could "probably do an even better job" than a medium format film model.

"I think the lenses are now the challenge. [They] are now the weakest part of the camera. You can have a 100MB 16-bit image, yet if your lens is not up to par, it doesn't matter, you might as well have a 10MB file."

Chuck's previous photographic roles included stints at National Geographic and he was a staff photographer at the Los Angeles Times. Now, he spends his time photographing wine-producing regions across the globe for books, professional assignments and his website, wineviews.com.

According to his wife Daphne, Chuck was one of the last photographers of his generation to move over to digital. Now, he doesn't see himself going back after seven or eight years on the other side.

On assignment in the film days, Chuck says that every time a photographer made an exposure they had "no idea" whether or not they got the photo or not. "The first person to look at that was going to be an editor in Washington. Every shot's gotta count." Now, the photographer has the scope to edit, crop and present a finished image before it gets reviewed.

"In the early days of digital, the histogram was critical. You can't spill over in the black point because on the printed page it's going to get muddy. You've got to have some information on the white side so that when it's on the press that won't become a blank." Now, he says that watching your histogram and being that precise doesn't matter all that much anymore, "because the printed page is going away."

"Pure photography is almost history. When we look at National Geographic, Time ... they're no longer using a pure photograph on the cover to sell the magazine. It's illustrations. It's photographs that are manipulated. They have decided that that's what the reader wants."

"Who wants to open a magazine when you can look at your tablet, phone or computer and get sound and visuals and better colours?"

Maybe for nostalgia's sake, those users will have Bliss as their device's desktop background. Closer to home, Daphne still has the wallpaper gracing the desktop of her home computer.

As for any future Microsoft wallpapers being captured by Chuck's camera, he remains hopeful. "I sent them my phone number but nobody's called yet for another photograph!"