Iain Frazer, 68, was caught after police executed a search warrant at his cottage in Gate Burton, near Gainsborough.
Lincoln Crown Court heard officers carried out the search after receiving information that indecent images of children were being uploaded at the address.
David Outerside, prosecuting, said Frazer was co-operative and police seized two memory sticks and a computer tower from the property.
Mr Outerside told the court indecent images were found on all three devices.
In total there were 80 still images in the most serious Category of A and 32 moving images.
There were 206 still images in Category B with 12 moving images, and 152 still images in Category C with 19 moving images.
Mr Outerside added: "The age range of the children was from three up to 14, and the images were of boys and girls."
Frazer, of White Cottages, Gate Burton, admitted three charges of making indecent images of children following the search on 10 August last year.
"In short he made full admissions", Mr Outerside said.
The court heard Frazer had an "impeccable record" with no previous convictions and was keen to engage with the probation service to ensure it did not happen again.
Andrew Swaby, mitigating, said Frazer could offer no rational reason for his behavior.
"He served in the Army for 36 years," Mr Swaby added. "He is heavily involved with the local community and church."
Passing sentence Recorder Adrian Reynolds told Frazer downloading images was not a victimless crime.
The Recorder said: "At the age of 68 it is pretty sad to see a man of your years and distinguished history sitting in the dock."
But the Recorder added that Frazer had made full admissions and passing a short prison sentence would not get him help.
Frazer was sentenced to eight months imprisonment suspended for two years with a 35 day rehabilitation requirement.