Chai Rachawat, a cartoonist for a prominent daily newspaper, posted pictures of Yingluck on Tuesday accompanied by the words "... A prostitute is not an evil person, the hooker only sells body. But an evil woman sells the nation".
His post apparently took aim at the premier's appearance at a democracy forum a day earlier in Mongolia where she gave an unusually fiery speech condemning the 2006 overthrow of her brother Thaksin in an army coup.
The lawyer also filed two further claims -- one for libel and one under the contentious computer crime act, he added.
Combined, the charges can carry a maximum sentence of 10 years in jail, a second police official said requesting anonymity.
More From This Section
In her address to the conference in Ulan Bator on Monday, Yingluck decried "anti-democratic forces" in Thailand for toppling her brother -- who now lives in self-imposed exile but maintains a deep influence over Thai politics.
Her speech caused uproar in the bitterly politically divided kingdom, with rival academics and senators demanding the premier swiftly apologise for her comments.
A lawmaker from Yingluck's Pheu Thai party condemned the cartoonist's post as "a violation of women's rights and insult on women" that defamed the premier.
"Chai Rachawat's defamatory comment calling the country's leader a whore is totally unacceptable," MP Jarupan Kuldiloke said in a statement on behalf of the party's women lawmakers.