As the fiercest storm of this century hit NSW this week, keyboard warriors cloaked in the warm glow of their desk lamp had their thumbs pulsing between the C and V keys, copying and pasting crocodiles into Lewisham station and sharks into Broadway shopping centre.

"I knew it!" potential tourists with a perennial fear of Australian wildlife cried, as the great whites manouevred between the coral and the escalators while the crocodile blocked the exit to Thomas street.

All the while the golden showers that traditionally pour from the Harbour Bridge on New Year's Eve took on a bleaker tone. As the city took a drenching, so did the view, locals mopped about gazing at what had become Sydney's Niagara falls for a day.

And just around the corner there were some gnarly barrels to be had.

The storm of the century had provided the swell of the decade, 14 metres on the coast had turned into three feet on the reef break at Bennelong point and one plucky grommet wasn't missing out.

Onto the left-hander he pounced, one cutback - two, and he was on his way to a towel at Mrs Macquarie's recliner.

Only he wasn't. This surfer never had to leave his swivel chair to thrash the waves that break upon the Opera House's steps, a little effects work, completed over three years ago, was all that was needed to fool radio personalities, twitterati, and this humble reporter.

And yet in the rough and tumble of storm coverage its the most the subtle, seemingly spontaneous, grainy amateur shots that cause the most trouble.

Tempe tower, with all its funnel like giant concrete quality looked as though it was going to fall over - tumble therewithal onto the unsuspecting domiciles below.

A call to Marrickville Council would follow - "not ours," the response. Sydney Water? "Geez - no way, that looks impossible," indeed. "But it's not ours anyway - try Sydney Airport."

As it happens [for those enchanted] Tempe Tower belongs to Sydney Airport, and it is not falling over.

The practice of photo-shopping, effects rendering and other image internet shenanigans have been part and parcel of natural disasters in the digital era.

Sam Hinton, an expert in digital forensics from the University of Canberra, said that many internet pranksters simply could not resist the challenge of getting all the major networks to pick up their fake photos

"People want to show off their skills, it is no different to hacking," he said. "We are so used to the idea that an image never lies that we take it at face value and people take advantage of that."

It is a practice that is only becoming more prevalent in the social media era as programs become more and more user friendly, said Dr Hinton.

"Tourist guy," affectionately known as "Waldo" is credited as being one of the first internet photoshop phenomenons.

Perched atop the World Trade centre, Waldo posed for a holiday snap as American Airlines flight 11 made its final tragic plunge into history.

The story of the photo became its myth, a final moment of innocence plucked from the wreckage of the World Trade centre.

Disappointment was met with outrage when it turned out Waldo was last atop the centre in 1997.

Hurricane Sandy took 157 lives and cost an estimated $US65 billion when it thrashed Eastern coastline of the United States in 2012.

It also provided fertile ground for photo-shop enthusiasts to flood Times Square and put everyone's favourite eight-foot fish between the suburban houses of Queens.

So how does one spot a fake half an hour before that call to the authorities at Sydney Airport?

Dr Hinton has these tips: 

1. Look at the edges of the different objects in the photograph. If they are very sharp or very blurry it is likely to be a fake.

2. Examine the light falling on those objects. If the light hits them from two different directions, fake.

3. Check out the shadows, if they are falling in the same direction - you get the idea.

4. Run a google search on the scene of the photo or objects within it. It's highly unlikely the cheeky photo-shopper has used their own photos, if it is fake you will be able to spot objects taken from other photos fairly quickly.

5. If you haven't spotted it by now, run it through open-source image analysis software available on the internet. The program will pull apart the errors in the photo. Every time a new element is added it will have a different total number of errors, which are introduced each time a photo is compressed.

Happy sleuthing.