Through me the way into the suffering city, through me the way to eternal pain.Dante Alighieri, Inferno
Most of the pictures on black metal sleeves were made by men who died before recorded sound was a commercial product. That is the first thing to establish, because it is routinely missed by people who describe the imagery as if it had grown out of the ground somewhere north of Bergen. A genre that presented itself as having no ancestors was in fact running a careful and rather scholarly raid on nineteenth century European painting, and paying nothing for it, because the painters were beyond invoicing.
The second thing is that the raid was not lazy. Somebody had to know which pauper, which hunt, which funeral, and the choices are consistently better than the budgets deserved. Read alongside corpse paint and the rest, the sleeves turn out to be the most deliberate part of the whole code and the part with the longest memory behind it.
The dead painters worked for nothing

Recorded at Heavenshore Studio in Stockholm in February 1988 and issued on 17 October that year, Blood Fire Death put Arbo's Åsgårdsreien on the front of a metal record and set a habit that has not broken since. The painting dates from 1872, it shows the Wild Hunt riding out of the sky, and it was itself made after a poem by Johan Sebastian Welhaven. So the sleeve is a picture of a poem about a folk belief, three removes from anything the band did, and it worked so completely that the Wild Hunt has since become common property across metal and its festivals.
Quorthon went back to the same well two years later. Hammerheart, recorded at the same studio between June and August 1989 and released by Noise on 23 April 1990, carries The Funeral of a Viking by Frank Dicksee, an English academic painter with a knighthood and no conceivable connection to any of this, the image supplied by a municipal gallery in Manchester. The founding picture of Viking metal came out of an English civic collection, on loan. Nobody involved seems to have found that awkward, and there is no reason they should have.
The economics explain the pattern faster than any theory about the northern soul does. A band pressing five hundred copies through a label run out of a bedroom cannot commission an oil painting, and in 1993 there was no stock library to raid either. What there was, in every public collection in northern Europe, was a body of national romantic painting that had been made to do exactly this job a century earlier: to make a stretch of country look older, colder and more populated by the dead than it is. The bands took it because it was free, and they kept it because it was correct.
Necrolord painted the ones that were paid for

The one indispensable living painter came out of the same scene as his clients rather than out of an agency, which is why the covers sit inside the records instead of on top of them. Kristian Wåhlin, born in Gothenburg on 4 December 1971, was playing guitar in Grotesque at seventeen and went on through Liers in Wait, Decollation, Diabolique and The Great Deceiver while producing, under the name Necrolord, cover art for more than a hundred and fifty releases.
The run between 1990 and 1996 is the spine of the whole visual period: Tiamat's Sumerian Cry in 1990, Therion's Beyond Sanctorum in 1992, Dissection's The Somberlain in 1993, Emperor's In the Nightside Eclipse in 1994, then in 1995 alone Storm of the Light's Bane, Dark Tranquillity's The Gallery and At the Gates' Slaughter of the Soul, and Bathory's Blood on Ice in 1996. One man, two genres, most of a decade.
Ask him where the pictures come from and the answer lands in the same century as the borrowed ones. He has named Caspar David Friedrich, Albrecht Dürer and Hieronymus Bosch among his early influences, which is to say a German romantic, a German engraver and a Netherlandish painter of the fifteenth century. Even the commissioned work is drawing on the same stock. The genre did not have a house style so much as a house library, and everybody was borrowing from the same shelf.
The photograph did the other half
Not everything was painted, and the half that was not is the cheaper and in some ways the more radical half. A high contrast black and white photograph costs a film, a friend and an afternoon. It also makes a claim a painting cannot make, because a photograph asserts that the thing in it happened, and a band standing in a wood in full paint in front of a camera is producing evidence rather than illustration. That strand has its own conventions, its own borrowed painters behind it, and enough weight to carry an argument on its own.
The modern guild draws rather than paints
What replaced the oil painting was the drawing board, and the change of tool is a change of argument. Zbigniew Bielak, born in Kraków in 1980 and trained as an architect, has produced covers for Watain, Mayhem, Absu, Deicide, Paradise Lost and every Ghost studio album but the first, and the work is architectural in the literal sense: elevations, cutaways, reliquaries, anatomical plates, everything ruled and labelled and rendered with the patience of a man producing a document rather than a mood.
The genre stopped asking for a picture of the abyss and started asking for its floor plan.
That is a real shift and it maps onto the music. A scene that in 1993 wanted a frozen wood at dusk wanted, by 2015, a diagram of a cathedral it intended to desecrate. The romantic sublime is a mood and it cannot be argued with. An architectural drawing is a claim, and claims can be checked, which is a more confident position for a genre to occupy after twenty five years of being told it was all posture.
What the borrowing actually means
None of this is a charge of fraud, and the people who use it as one have misunderstood the operation. Black metal did to European painting exactly what it did to Venom, Bathory and Hellhammer musically: it took an existing body of work, stripped the parts that flattered the audience and kept the parts that did not. Arbo's riders were painted for a bourgeois drawing room and end up on a record about the end of the world. Dicksee's Vikings were an English fantasy of the north and end up defining a Swedish subgenre. Kittelsen drew plague for a country that had largely forgotten it and supplied a soundtrack he never heard.
The images were not found in the forest and they were not dreamt up in a basement. They were selected, from a specific century, by people who knew what they were looking at, and the selections have held for thirty years. Which particular sleeves did the most work is a separate question with a separate answer, and it is set out in the Iconic Black Metal Album Covers. For how the pictures fit the records they were wrapped around, go back to the story so far.