Can sometimes have "Dead or Alive" as the bottom line.
Comedic versions may add "(Preferably Dead)"
So pervasive that it doesn't just appear in westerns. In modern settings, they're almost exclusively seen in post offices.
The FBI still does these.
One common idea is for a character to see his poster and do one of a few things:
Draw something on the poster to make the face look different from the real one, like a moustache. Bonus points if someone then captures an unrelated third party who just happens to look like the altered drawing.
Luffy and the crew have these in One Piece. Wanted Posters are sometime thought to work like Power Levels in One Piece (the value actually correlates to how much the World Government views those particular people as threats to their power), and some double as gags, like the orignal ugly poster of Sanji (the authorities didn't have a photograph of him, so they did a sketch based on descriptions—and then started chasing after a guy who looked like the sketch) and the 50-Berry reward for Chopper (considered the crew's "pet" by the authorities), who might actually be one of the strongest members of the crew.
Laharl: Ten millions? Etna:(faking it, as she's the one responsible) Amazing! That's my prince! Laharl: That's all they think my life is worth? (angrily destroys the poster)
The second manga series, localized in North America as Lupin III: World's Most Wanted, used the Wanted Poster layout as the cover art for each of the volumes. Sometimes fans have made wanted posters of the four thieves, as well.
As a foreshadowing of later events, an early episode of Fullmetal Alchemist: Brotherhood has one scene showing a row of wanted posters of people who committed crimes against the State Military — they are sketches of Yoki, Scar, and Greed. Yoki's is interesting in that Brotherhood cut out the incident from the manga where he was defeated by the Elrics, and he's instead only introduced once he's on the run.
There's one warning about the famous Gentleman Thief Phoenix in Honey Honey No Suteki Na Bouken, apparently in Japanese in the middle of Austria. The warning is also only useful to the Princess, because he's after her ring, the Smile of the Amazon. Apparently everyone in back alleys need to know, too.
Often used in Lucky Luke for gags, especially with the Daltons. Notably in Daisy Town, the posters of the brothers are shown throughout their childhood and teens until adulthood, with the reward money for their capture steadily increasing — except for Averell Dalton, which keeps being $7.
The Man With No Name uses one to lampshade the fact that the comic's Blondie looks nothing like Clint Eastwood, with a character commenting on "these new Wanted posters which show how he's changed his appearance".
In Mandatory Retirement, Wedge is teased about getting marriage proposals in the mail. His friend says it's because he looks handsome on the wanted posters, and Wedge says they just want the reward.
In one Knights of the Dinner Table story, Bob and Dave are annoyed at the low prices on their Cattlepunk characters' heads, and start committing increasingly outrageous crimes to rectify the situation. This backfires when the rewards get so big that Brian and Sara decide to turn them in and collect.
The covers of all issues of Bad Guys, a Gargoyles spin off, features wanted posters of the characters.
Runaways has a cover featuring the main characters on a wanted poster.
This◊ infamous and endlessly homaged X-Men cover (X-Men #141).
In a gag of the Dutch comic Gilles de Geus, robber Gilles has to get into the city to get groceries, but wanted posters of him are hanging all around the city gate. He goes to great lenghts to get into the city while avoid getting recognized, but all results fail. Fortunately for him, by the time he gives up and the guards at the gate finally manage to compare the picture on the poster with his face, an unnamed person has already vandalised the poster so the guards don't recognize Gilles and allow him entrance to the city.
Mickey Mouse nemesis Black Pete had several of those in one episode and kept ripping them.
The early comic issues of MAD often used these as background gags:
"Mole" (#2) had a reward of 20,000 rubels posted for Josef Stalin, "WANTED DEAD!"
"Sane" (#10), a Western parody, had a wanted poster in Yiddish.
"Mickey Rodent" (#19) had a poster for a "horse thief" known as Black Booty who "is armed with a colt," showing two bandit-masked equine faces.
So did the Soviet cartoon adaptation of Cipollino.
The FBI sends these around in Beavis And Butthead Do America; people keep recognizing them and calling the cops, but the kids are so stupidly unpredictable that they keep walking right out of the dragnet.
Pictured: Tangled has Flynn's Wanted Posters, which they never get his nose right.
This is how we're introduced to the protagonists of The Road to El Dorado, establishing their status as partners in crime.
Films — Live-Action
In For a Few Dollars More, the first villain we see added two zeros on his own wanted poster, claiming it wasn't anywhere near enough.
The Good, the Bad and the Ugly features a wanted post for Tuco (the Ugly) emblazoned with a humorously anachronistic high-res photograph of the outlaw.
In one movie, Harpo Marx has a copy of his wanted poster ("Wanted for Jaywalking") attached to the inside of his coat.
In Shanghai Noon, Chon Wang and Roy O'Bannon find wanted posters for themselves. Roy is annoyed on how much is offered for Chon Wang, as he's just a "sidekick", and Chon is annoyed as the poster calls him the "The Shanghai Kid", and he's not from Shanghai.
In Wrongfully Accused, the hero, Ryan Harrison, comes across his own Wanted poster in a fishing shop. He quickly scribbles a ridiculously long beard, an oversized pair of glasses and a comically small bowlerhat on it. Shorty after, the sheriff arrests a man with a long beard, wearing an oversized pair of glasses and a comically small bowlerhat.
In The Good, the Bad, the Weird, the Good, a Bounty Hunter checks out wanted posters early in the film, and there's a scene where the Weird complains about the relatively low bounty on his head. Gets an interesting call back in The Stinger during the credits showing that the Bad was killed off, as his poster is crossed out and taken down. The Weird gets a new poster with a much higher bounty, in light of his crimes during the film and revealed status as a Retired Monster. He's then briefly shown traveling on the road and having made a cool Evil Costume Switch.
In L: change the WorLd, after Maki runs away the bio-terrorist group ringleader, K, goes on TV and declares Maki to be a medical patient with a deadly virus who must be detained at all costs. This, along with the wanted posters plastered absolutely everywhere, makes it very difficult for Maki and the others to move—especially since K is an acclaimed scientist, so no one doubts the story.
WANTED: Bud (Alkali) Abbott — shoots first...runs afterwards! WANTED: Lou (Killer) Costello — trigger-shy sheriff! WANTED: Marjorie (Calamity) Main — the pistol-packin' "Ma Kettle!"
In The Naked Spur, bounty hunter Howie Kemp is using a wanted poster in his chase after a fugitive murderer. He tears off the bottom part, which advertises a $5000 reward, and gets two other men to help him by letting them think he's a lawman. After they catch the bad guy, said bad guy reveals his own copy of the wanted poster, which includes the reward, leading the other two men to demand their shares.
Across the Bridge (1957) is about a found-out American Corrupt Corporate Executive who has to go into hiding as his picture is all over the news. He assumes the identity of a Mexican passenger he meets on a train. Soon he find out that that person was a criminal too, with money on his head (dead or alive).
A Running Gag in the Belgariad and The Malloreon is Silk appearing on wanted posters. He generally reacts with disdain, though he has occasionally felt flattered by high reward offers. Beldin also gets this treatment in Mallorea courtesy of Urvon, a disciple of Torak that he has a long-standing vendetta against — involving a smoking hot hook and the latter's guts.
Lolita. After kidnapping and sexually molesting Dolores Haze, Humbert Humbert walks into a post office and sees various posters for these crimes. He thinks that if his story is ever made into a movie, they should dissolve one of these posters to his own face. The 1997 movie adaptation obliges (albeit in a Deleted Scene) when Jeremy Irons imagines his own face on a poster, wanted for violations of the Mann Act (transportation of females across state lines for immoral purposes).
In Where's Wally? in Hollywood, "The Wild, Wild West" has two wanted posters on the jailhouse wall, with "$10,000" under one face and "10 cents" under the other.
Commonly show up in Kaizoku Sentai Gokaiger, as the Evil Empire has put out a bounty for the crew. The reward on each member goes up every few episodes — Butt Monkey Don Dogoier always has the lowest amount. And during the end of the run, the reward for capturing Marvelous skyrockets to a crazy amount. How? How does UNLIMITED REWARD sound? They've pissed off the Empire when that bounty went up.
One will occasionally turn up in Kung Fu: Caine is wanted by the Chinese government for killing the Emperor's Nephew. "$10,000 Alive, $5,000 Dead." A likeness of Caine is drawn on the posters, along with drawings of his forearm tatoos/brands.
Honorable Mention: One of Dom Jolly's Trigger Happy TV pranks was to get a random passerby to do something embarrassing for him, and then walk away, leaving them on (hidden) camera looking confused. He'd do it standing under a giant billboard with a picture of himself, and the words "Don't Trust This Man".
Farscape uses "wanted beacons", which show holograms of the criminals (usually Moya's crew) with narration explaining the reward for turning them in.
Pair Of Kings: Brady's criminal alter ego "Scirocco" had his picture in a wanted poster reading "Barely Alive".
El Chapulín Colorado once helped a western town to post wanted posters with the criminal's face and the inscription "Lo Queremos Vivo o Muerto - Mucho Cuidado". (Roughly "Wanted Dead or Alive - Caution") When confronted by the criminal Chapulin tried to appease him by ripping a piece of the poster so it's red "Lo Queremos Mucho" (Very Wanted)
A Western-themed episode of The Benny Hill Show had a few Wanted posters. One is about a man wanted for arson, who promptly torches the poster.
Cats features a poster reading "MACAVITY: WANTED FOR EVERYTHING." Making the line about how "he always has an alibi" an Informed Attribute, but then everything about Macavity seems to be, except for the part where he's evil.
Guybrush gets his very own in Monkey Island 2: LeChuck's Revenge, which is continually updated as your list of crimes keeps growing. Altering it is part of solving a puzzle.
Zack & Wiki: Quest for Barbaros' Treasure makes clever use of this trope: it's shown as a sort of ranking screen, as you do great acts of piracy/solve puzzles, the bounty goes up, and the fidelity of the sketch on the poster increases, starting from wildly inaccurate (not to mention looking like a six-year-old drew them) and ending at a dead ringer, then going on to photographs of increasing clarity.
In World of Warcraft, wanted posters act as questgivers, and the quests usually involve killing a boss and bringing something from them to an NPC as proof of their death.
Having a bounty on your head is apparently something of a status symbol for Skies of Arcadia's Air Pirates. At one point you see a poster that clearly has the viewpoint character on it, but no-one acknowledges this.
Sundown Kid in Live A Live. He actually put the bounty on his own head so someone would take his life.
Assassin's Creed 2 has these pop up whenever you start performing evil (or impressive) acts. Ezio can then tear them down to become anonymous again (as well as by bribing town criers and killing bad-mouthing politicians in broad daylight.)
Bowser is on one of these in Mario Party, as well as in Western Land in Mario Party 2, complete with cowboy hat and pistol, under the name 'Bowser the Brash'.
In the canceled Warcraft Adventures: Lord of the Clans, Thrall learns about Grom Hellscream by finding a wanted poster for him in Durnholde.
In Spelunky, "Wanted" posters appear in shops a level after you commit a crime to a shopkeeper. When you're declared innocent (don't kill shopkeeper nor steal from him for another few levels), they disappear.
Gun Smoke shows a wanted poster before each round, though the relevant text is displayed beside it rather than on it.
The Bard occasionally finds wanted posters of himself in The Bard's Tale. Incredulously, he somehow has the gall to sell them back somewhere, because they're worth money just like any other collectible.
In the arcade version of Double Dragon, wanted posters of the game's bosses can be seen in Mission 1 and Mission 3. The award for Machine Gun Willy, the final boss, is $100,000, ten times more than the other bosses (who are only worth $10,000 each).
BlazBlue. Ragna the Bloodedge, being a wanted criminal, had a wanted poster. Unfortunately, in his own words, the artist just drew him in a style of Gonk that it's near impossible to realize the guy in the poster is the same as Ragna.
In 1866, there is such a poster in each large town. It triggers some bounty hunting quests and tells why the man has been wanted, sometimes in a humourous way ("raping the horses and riding off on the women"). Note that the quest is completed wheither the target is killed or captured alive.
Each of the playable characters of Borderlands 2 have a wanted poster with bounties that are generally up in the billions. Their crimes may range for Assassination (Zer0), War Crimes (Axton), or Excess Adorability (Gaige). One of Krieg's DLC heads actually has him wear his wanted poster as a mask.
Dynamite Dux has several of these in the Texas level, each showing a cat-looking thing.
In the intro for Skullgirls, each of the playable characters is shown in what appears to be a movie poster...except for Ms. Fortune, who has a wanted poster.
Jazz Jackrabbit had "KILL this rabbit" posters out for the title character.
Avatar: The Last Airbender has about six of them (Aang, Jeong Jeong, Chey, the Blue Spirit, Iroh and Zuko). Oddly, they never made one for any of Aang's friends.
Toph got one for her antics in "The Runaway". She couldn't see it, of course, but she keeps it anyway.
The Looney Tunes short Drip-Along Daffy has villain Nasty Canasta standing in front of his own wanted poster, then stepping away from it in a memorable reveal.
Rebel Rabbit has Bugs Bunny notice that the reward for capturing a rabbit (any rabbit) is a paltry 2 cents, and the whole plot is him committing crimes to get the reward up. He gets captured in the end.
In the Wartime CartoonConfusions of a Nutzy Spy, one of the wanted posters is of a pin-up girl with no crime alleged, but a note attached saying "and you ain't kiddin', brother!" and signed "U.S. Army."
The Donald Duck cartoon Donald's Crime has him trying to tear away his wanted poster, but reveals another poster underneath with a higher price on his head. Donald keeps tearing off until the zeros go past the poster and into infinity.
A Mickey Mouse cartoon featured Pete's wanted poster. The reward was $ 1,000 (dead) or $ 100 (alive).
Kim Possible has mug shots of Dr. Drakken and Shego on the inside of her locker door, though we never really get a good look at the pictures.
Megas XLR: The episode "Universal Remote" starts with the Monster of the Week, Skalgar, seeing his own wanted poster and being outraged at the low reward that is offered for him.
In The Simpsons, when Milhouse disappears due to the stress of playing Fallout Boy, a wanted poster is issued. Below his picture is "Dead or Alive", with "dead" crossed out.
Bounty Hamster. Having already tired of her inept Bounty Hunter in the first episode, Cassie resolves to find her Disappeared Dad herself. She puts up a wanted poster, only to realize she's pasted it on the side of a Rock Monster instead of a wall. Then it turns out the alien language on the poster has been incorrectly translated, describing her father as an intergalactic Big Bad wanted dead or alive (and offering Cassie as the Standard Hero Reward). Cassie and Marion have to chase down and stop the swarm of bounty hunters who have taken up the offer.
The My Life as a Teenage Robot TV movie "Escape from Cluster Prime" features a poster of Jenny reading "Wanted — Plugged or Unplugged".
The Heckle and Jeckle cartoon "A Merry Chase" starts off with Chesty the Bulldog and Dimwit putting up Wanted posters of the two magpies.
Variant: For the second Iraq war, the US Military issued a deck of cards with 52 mini-wanted posters for various Iraqi baddies.
In at least one instance in Great Britain, a police Identikit profile of the wanted man for a serious crime was broadcast on the TV investigation show CrimewatchUK, which led to an wholly innocent person being repeatedly fingered for the crime by members of the public, as he looked so like the wanted criminal. The show had to broadcast an apology and a declaration that this person had no connection whatsoever with the crime. Apparently this sort of thing happens a lot.