This is a classic image of blackface, a white person wearing makeup to mock black people:
Note the exaggerated lips and the unnaturally dark skin—blackface was done with black shoe polish or a very dark skin dye to make a white person look like a black version of a whiteface clown.
Some people think any attempt to portray someone of another race is racist. They say this white model portraying a black woman is racist:
And Beyonce Knowles betrayed all black and Asian Women by modeling as a white woman:
Beyonce was also accused of doing blackface when she darkened her skin:
If you accept the logic that portraying someone of another race is always racist, John Howard Griffin's Black Like Me is a racist book; when segregation was legal in the US, he darkened his skin and hair to have a first-hand experience of being black:
Whites who play Othello get accused of doing blackface:
But people rarely accuse Orson Welles of blackface because he plays the character with respect:
While Lawrence Olivier's makeup and eye-rolling crosses into parody:
The question of respect for the character is crucial. Harry Connick was caught up having to judge a bad parody of the Jacksons in Australia:
These people aren't parodying the individual Jacksons; they've made themselves up to look like golliwoggs, and the humor comes from the idea of, as Connick puts it, portraying black folks as buffoons.
That's the simple rule for deciding whether someone is indulging in blackface: If they're mocking a race by pretending to be of that race, they're being racist. If they're not, they should be prepared for identitarians to misunderstand. But ultimately, we're all human. If you want to look like your race or sex or age or class is different, that's your right as part of the human race.
Which applies to non-human races, too. Here's a cultural artifact from the 1960s:
See also: racism at Racialicious, or Florence + The Machine and Bali