The dog was found in parkland in Perth last week
An animal charity has described the owner of a dog dumped suffering from a huge mouth tumour as "cowardly" and "callous".
The elderly Jack Russell was found in parkland at South Inch in Perth last week. The tumour was so large it had broken the dog's jaw.
The severity of the condition forced a local vet to put the animal to sleep.
The Scottish SPCA is appealing for anyone with information about the dog or its owner to contact them or police.
The charity's chief inspector Brian Cowing said the dog was found lying on grass beneath a tree, close to a public footpath in the park.
He said: "Someone must have put him there because he was not well enough to have walked there himself.
"He had a mouth tumour on the inside of his mouth and it was so big that it had caused his jaw to dislocate and break.
"We would estimate that he had been suffering from the tumour for two to four months due to its size and the damage it had caused to his mouth."
Because of the condition the animal was not able to eat.
Mr Cowing added: "We believe that someone has ignored this dog's condition for quite some time and instead of taking it to a vet they have simply dumped it.
"Not only is this a cowardly and callous thing to do, it is also an offence that carries stiff penalties."
Anyone found guilty of abandoning an animal can face up to six months in prison, a £5,000 fine or both. They can also be banned from keeping or owning animals.