Jake Cannon of Llanelli, Carmarthenshire said he had no sexual interest in the images himself, he just wanted to sell them to make money.
The 22-year-old admitted possessing and distributing indecent images of children.
Swansea Crown Court heard the expert who examined the images described them as the worst he had ever seen.
Cannon told police he had been swapping indecent images since he was 13-years-old.
Recorder Peter Rouch, said Cannon had been, in effect, continuing the abuse of children by both seeking out such material and then passing it on to others.
Welcoming the sentence, a NSPCC Cymru spokesman said: "The shocking scale of Cannon's offending and the particularly horrific nature of these images is deeply disturbing.
"Every single image represents a crime scene and behind each is a young victim of abuse who will need support to recover from what has happened to them.
"Those who distribute this appalling material are responsible for increasing its proliferation and - inevitably - leading to more children being abused."

Mr Zuckerberg made the announcement in a letter to Max on his Facebook page.
He said they were donating their fortune to the Chan Zuckerberg Initiative to make the world a better place for Max to grow up in.
The donation amounts to $45bn (Â£30bn) at Facebook's current value.
However the shares will not be donated to charity immediately, but over the course of the couple's lives.
Were Mr Zuckerberg to give away 99% of his shares immediately, he would still possess hundreds of millions of dollars. Ms Chan's worth has not been documented.
Max was born last week, although her birth was only made public on Tuesday.
In his letter Mr Zuckerberg said the aim of the Chan Zuckerberg Initiative is "to advance human potential and promote equality for all children in the next generation".
Its initial areas of focus will be personalised learning, curing disease, connecting people and building strong communities.
"Your mother and I don't yet have the words to describe the hope you give us for the future," Mr Zuckerberg said at the start of his letter to Max.
"You've already given us a reason to reflect on the world we hope you live in," it added.
Where should Zuckerberg put his money?
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The great Facebook giveaway
Dave Lee, BBC North America Technology Reporter, San Francisco
Billionaire investor Warren Buffet congratulated Zuckerberg and Chan, proclaiming that when it comes to giving away your fortune, "30 is the new 70".
No longer should billionaires wait to die before handing over money to a different generation, Buffet said, in a gushing approval of Silicon Valley's newest and most influential power couple.
Everything Mark Zuckerberg does is eyed with intense scrutiny, not least due to the nature of Facebook's business of making money from personal data.
But while the 31-year-old's previous charitable efforts have been criticised for being too focused on building Facebook's user base, this latest pledge appears to leave the Facebook business to one side.
It's a continuation of what we've seen developing over the past six months, where Zuckerberg appears at ease hosting heads of state as he does in the company of his own development team.
The days of Mark Zuckerberg being seen as a nerdy, awkward tech dork are well behind us.
His ambition now is clearly to be a significant figure on the global political stage.
Read more: Silicon Valley's new power couple
The letter highlighted the important role of technology in achieving the couple's goals of advancing human potential and equality.
"Many of the greatest opportunities for your generation will come from giving everyone access to the internet," Mr Zuckerberg wrote to his daughter.
He said more details about the donation will be released once he and Ms Chan return from paternity and maternity leave.
Mr Zuckerberg said he will remain chief executive of Facebook for "many, many years to come".
In a filing to the US Securities and Exchange Commision, Facebook said that Mr Zuckerberg "plans to sell or gift no more than $1bn of Facebook stock each year for the next three years and that he intends to retain his majority voting position...for the foreseeable future."
A man who claimed to be a professional distributor of child abuse images has been jailed for 15 months.
[NEXT_CONCEPT]
Facebook's Mark Zuckerberg and his wife Priscilla Chan say they will give away 99% of their shares in the company to good causes as they announce the birth of their daughter Max.