Instagram: The sewer of the web?

A post found under the thynspo search term, before Instagram banned it. Source: Supplied

WE KNOW Instagram has been revolutionary. It's easily one of the largest repositories of sunny selfies, date night gelato pics and self-affirming quotes in the world.

But this is the internet, where humans ruin everything - even a network of happy snaps.

Every social network has a creepy back alley, but this is not pretty. And critics say the app's lax moderation standards are to blame.

CHILD PORNOGRAPHY

One of the child pornography distributors on Instagram. The account has more than 900 followers. Picture: Instagram Source: Supplied

It's the vilest of the vile: pedophile networks sharing images of abused boys on Instagram. More than 900 people were watching a 'young boys' account above, discovered by horrified Australian adult business owner Vivica Delicious who reported the site to the Australian Federal Police and to Instagram.

The accounts were recently been removed after online activists contacted Instagram, but Ms Delicious was critical of the time taken to do it.

"They're quick to take down shots of women posting (lewd) photos, but they're much slower with more serious stuff," Ms Delicious said. Instagram has been contacted for comment.

DRUG ABUSE

A community of heroin and painkiller users glorifying their drug use - syringes, veins and all - has developed on the network.

A disturbing image of a syringe from the 'junkies of Instagram' feed. Source: Supplied

Their hashtag? #junkieig: "Junkies of Instagram".

Two Boeing 747s of us die each year because of prescription painkillers, Dr AlexWodak told news.com.au last year.

Prescription painkillers posted by the 'junkies of Instagram' community. Source: NewsComAu

Then there's something completely different. #babeswithbud. #weedwomen. #marijuanababes.

As social media trainer Stewart Dawes puts it: "It's beautiful women smoking bongs."

Mr Dawes said the app was "not great" with dealing with users.

An image from a pro-marijuana Instagram feed that has flourished without restriction. Source: NewsComAu

SELF HARM AND THINSTAGRAM

Other Instagram communities are more subtle.

One community of largely young woman -- which has uploaded more than a million images -- uses a codeword search term which serves a rallying point for people interested in anorexia or who wish to self-harm .

Instagram has already been forced to ban the sharing of "thinspiration" images that contain messages such as the following.

A post found under the thynspo search term, before Instagram banned it. Source: Supplied

DOUCHES

This guy, an Instagram character who posted a wide variety of images of the fruits of his riches - but was later exposed as a fake.

You can't rule against stupidity all the time.

This user was labelled Instagram's 'biggest douchebag' in April after repeatedly posting the fruit of his supposed riches

If you or someone you know may be at risk of suicide contact Lifeline 13 11 14, beyondblue 1300 22 46 36, or Salvo Care Line 1300 36 36 22.