Strachan and Rennie denied being involved in the network
The two men at the centre of Scotland's largest known child abuse network have been jailed for life.
Neil Strachan, 41, attempted to rape an 18-month-old boy while 38-year-old James Rennie sexually assaulted a three-month-old.
Strachan was sentenced to a minimum of 16 years in prison, while Rennie was ordered to serve at least 13 years.
Police said the operation had led to more than 200 suspected paedophiles, 70 of them in the UK, being identified.
Six other men had already been sentenced for their involvement in the network.
Strachan and Rennie, both from Edinburgh, were also found guilty after a 10-week trial of conspiring to get access to children in order to abuse them, while Strachan was convicted of a further charge of sexually assaulting a six-year-old boy.
This, in my judgment, can be properly described as a dreadful crime
Strachan, who is HIV positive, has already served a three-year prison sentence in 1997 for abusing a boy. Rennie was the chief executive of LGBT Youth Scotland, which offers advice to young gay and lesbian people.
Passing sentence on the pair, judge Lord Bannatyne referred to Strachan's abuse of the 18-month-old boy, which was captured in a photograph known as the "Hogmanay image" because it was taken on New Year's Eve in 2005.
The judge told Strachan: "By its very nature, what is shown in that photograph is utterly appalling and would shock to the core any right-minded person who has had to see it.
"Over and above that, this offence involves the most gross level of breach of trust. You were invited into a house, treated as a friend of the family, and then entrusted with their child.
"You then breached that trust in the way shown in the 'Hogmanay image' in order to satisfy your base sexual interests. This, in my judgment, can be properly described as a dreadful crime."
Lord Bannatyne said Rennie had also betrayed the trust of the parents of his victim to a "truly appalling" extent.
The judge said Rennie, a trained teacher who was found guilty of 14 charges, was at the heart of the conspiracy to abuse youngsters, and likened him to a spider weaving an electronic web to bring about his crime.
The mother of Rennie's victim, known as Child F, told BBC Scotland of the "pain and torment" the case had put their family through.
She called for a "global strategy" between internet providers and government to prevent the distribution of abuse images.
"However, for those involved in paedophile behaviour to identify it in themselves and know where to seek help, society must be prepared to discuss this issue", she added.
Ian Livingston, Lothian & Borders Police: "I welcome the sentences"
"We need to allow an openness within society of where to seek help, just as alcoholics go to AA and gamblers go to GA.
"Clearly the protection of children must take precedence, but if individuals could have been stopped or deterred, we as a family may not have found ourselves in this situation."
Rennie had circulated pictures of the abuse and offered a boy to other paedophiles - an offer taken up by Strachan.
Both will remain under close supervision for the rest of their lives after the parole board sees fit to free them.
Defence counsel Mark Stewart QC said Rennie, who has no previous convictions, wanted to make a formal apology and place on public record his "shame and sorrow" at what happened.
Co-accused Colin Slaven, 23, from Edinburgh; Neil Campbell, 46, John Milligan, 40, and John Murphy, 44, all from Glasgow; Ross Webber, 27, from North Berwick in East Lothian; and Craig Boath, 24, from Dundee, were also convicted of various offences.
They were given prison sentences of between two and 17 years.
The men had been arrested during the Operation Algebra police investigation, which uncovered nearly 125,000 indecent images of children.
It is clear from the evidence in this case that the accused saw no limits on how far they would share, exploit and abuse children
Morag McLaughlin Procurator fiscal
Operation Algebra also uncovered dozens more suspects around the country and worldwide, many of whom have already been charged.
The investigation was sparked by a single indecent image of a naked 11-year-old which was found on paint company engineer Strachan's computer when it was sent for repair.
Detectives discovered that Strachan and Rennie had filmed themselves sexually abusing children before distributing the images over the internet.
The two paedophiles had been trusted by the children's parents to look after the children.
Lothian and Borders Police said their inquiry had led to more than 200 suspected paedophiles being identified internationally, and at least 70 in the UK.
Detectives have said there were further suspects in Scotland as well as Avon and Somerset; Devon and Cornwall; Merseyside; South Wales; West Midlands; Sussex; Essex; London; Thames Valley; and Hampshire.
Speaking after the sentencing, Morag McLaughlin, procurator fiscal for Lothian and Borders, said recent advances in technology were making it easier for the police to bring child abusers to justice.
She added: "It is clear from the evidence in this case that the accused saw no limits on how far they would share, exploit and abuse children in order to satisfy their own horrific sexual gratification.
"However, our specialist prosecutors will use the constantly improving technology available to the police to stop and bring to court those who think they are hidden by the anonymity of the internet."
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.