Total Film has a team of people that work on the cover each month. The editorial staff choose the content/theme - usually based on a key new release. The Picture Ed sources the artwork and the Deputy Art Ed lays the page out. Then everybody works together to write the headlines. The Production Ed proofs it all and then the Editor/Publisher usually sign off on it before it goes to press. The images are usually sourced from the film studios when it's a big new release.
The art guys occasionally use Illustrator and Photoshop, but mainly In Design.