There's an interview with Mike Winterbauer at Sega-16. The veteran artist is responsible for some iconic art of classic games of the 80s and 90s. He talks about his work for Might and Magic games:

Almost always I was given minimal information about the game I was supposed to do cover art for. One of the exceptions is the Might & Magic covers and the maps I did art work for, I was well-informed about the game and characters. Typically, I was handed screen shots and a synopsis of what the game was about. The games had a low-res quality about them, so the storyline and gameplay were integral to the success of the game. This enabled me to be very creative in coming up with a cool idea for the box cover.

The Might & Magic paintings I had a lot of time to paint. I worked on each of the pieces for well over a month, as there was plenty of time to paint each of them. They were all large paintings, being 30 by 40 inches on board, and I wanted each of them to be the very best I could make them. I hoped that the paintings would one day become valuable, and that is why I painted them larger, as larger collectible paintings can be highly sought after.