The usual cover process begins with a very basic brief from the editor.

-- Young Cyclops' eyes blasting uncontrollably.

-- Black Panther on throne, flanked by supportive Storm.

-- Black Panther fighting Killmonger.

-- Wolverine and Shadowcat leading the Knights of Wundagore into battle.

More often than not the covers are done ahead of interior art or even plots (to allow the cover to be promoted in catalogues.) Often so far ahead of interior art that details are sketchy (which has lead to the increase in generic, 'iconic', non-story specific covers).In the case of the Black Panther versus Killmonger cover there was no ref for Killmonger's armour so I designed that and rationalised three different BP armour designs.

Its normal to send the editor two or three roughs to select from.

With the drive towards 'painted' covers I've recently added crude airbush rendering to the roughs in the hope of having the colourist model and light the image correctly.