The first pictorial representation of Jesus Christ is insulting Roman graffiti that gives him a donkey’s head.
Early Christians used several different symbols to represent their faith: the cross, of course; various “christograms” (Christ’s initials merged into a symbol, such as the Chi Rho, the tau rho, and IX monogram); and the Jesus fish symbol. These symbols were necessary because the early Church had many enemies, not least of which the Roman Empire. Secret signs helped believers recognise fellow believers and avoid oppression. The fish symbol, known as the ichthys, was used for this purpose as far back as the 2nd century CE.
Not all depictions of Christians were favourable. A common slur – used against both Christians and Jews – was that they worshipped donkeys. The early Christian writer Tertullian noted this rumour:
In this matter we are (said to be) guilty not merely of forsaking the religion of the community, but of introducing a monstrous superstition; for some among you have dreamed that our god is an ass’s head – an absurdity which Cornelius Tacitus first suggested.Tertullian – Ad Nationes
And then dropped a classic Tertullian rejoinder:
Suppose that our God, then, be an asinine person, will you at all events deny that you possess the same characteristics with ourselves in that matter? Not their heads only, but entire asses, are, to be sure, objects of adoration to you.Tertullian – Ad Nationes
All of these elements – the secrecy of early Christianity, the rumours of donkey-worship, and the oppression of the Roman Empire – combined to give us the very first image of Jesus. It was found at the very centre of the empire, near the Palatine Hill, carved onto a plaster wall, and is thought to date to around 200 CE. It’s classical graffiti.
The creator of this image is unnamed, but he’s writing about a soldier named Alexamenos who is apparently Christian. Alexamenos is depicted in front of a crucified man; the man has a donkey’s head. The inscription is “Alexamenos worships his god.” Unbelievably, there are no earlier depictions of Jesus.
(End note: the exact dating of this graffiti, and whether it actually refers to Jesus or not, is disputed. Given the inevitable fog brought about by two millennia of intervening history, that’s unsurprising.)