A pervert who groomed and molested young boys had half a million child abuse images on his computer equipment, a court heard.
The number of indecent photographs found on Paul Webster's hard drive, laptop and a memory stick was so great that police officers were unable to analyse them all.
They featured young boys and covered all levels of seriousness, including ones which depicted bondage and sadism.
Maidstone Crown Court was told the 45-year-old also kept innocent photographs of the boys he abused - but doctored them with captions that were "graphically indicative" of his sexual fantasies.
He even used his work computer to access a large number of websites with links to child abuse and continued to download images while under police investigation.
The images were discovered after he had been arrested in relation to allegations of sexual offences against young boys dating back to 1999.
Webster, of Maple Road, Strood, initially denied any wrong-doing - but later admitted three charges of indecent assault, two of gross indecency, 14 of making indecent photographs of children and seven of possessing indecent photographs.
Jailing the storeman for three-and-a-half years, Judge Charles Byers said Webster groomed the boys to make them "amenable to your advances and also to ensure their silence".
Referring to the images, he said it was important to remember that those in them were real children.
"That is why the law is quite firm that such sentences must be custodial where such depravity is depicted and practised upon those children," he said.
Webster was also made subject to a sexual offences prevention order, banning him from having equipment capable of accessing the internet and from having unsupervised contact with boys under the age of 16.
He must also sign on the sex offenders' register for 10 years.
The abuse of the boys involved touching their genitals and making them touch him.
Prosecutor Christopher May said Webster "made a point of spoiling them" to gain their trust and confidence.
As well as the computer images, police found photograph albums containing pictures of two of his victims.
"Although they were not indecent they give an insight into the defendant's thinking towards these boys because he added captions which were graphically indicative of his sexual feeling towards them," said Mr May.
"There were also hundreds of photographs of young boys cut from newspapers, books and magazines."
"It demonstrated he was using his work computer to access a large number of sites which appeared to be connected with child porn," he added.Mr May also told the court that monitoring software was installed on Webster's computer at work after his bosses were "troubled" by his internet searches.
Webster continued to download photographs of young boys despite his initial arrest last year, he said.
Mr May said they were not indecent images but "consistent with a pattern of interest" in such material.
"I welcome the sentence in this case and hope time behind bars will give Webster the chance to reflect on what he has done..." - PC Leigh-Anne Lawrence
Paul Greene, defending, described Webster as having "conflict within him", which caused great shame.
"On the one hand he accepts there is sexual arousal but on the other hand he admits to feeling sick, knowing they (the images) are illegal and there is suffering behind them," he said.
Webster, who has a previous conviction for indecent assault on a man in 1991, has been in custody since March.
After the case, PC Leigh-Anne Lawrence, from Kent Police, said: "When officers examined Webster's computer equipment, they discovered hundreds of thousands of depraved images depicting the sexual abuse of children.
"Teams at Kent Police dedicate their careers to tracing and stopping the exploitation of children and will do all we can to stamp out the vile offences related to this.
"I welcome the sentence in this case and hope time behind bars will give Webster the chance to reflect on what he has done."