This is a correction and a suggestion to the original post.
Actually the only thing the artist needs to do is create the wall paper in a certain aspect ratio. 800x600, 1024x768, 1600x1200 all share the same aspect ratio of 4:3 and 1280x1024 has a unique aspect ratio of 5:4 and then you have 1280x800, 1440x900, 1680x1050 and 1920x1200 which share an aspect ratio of 8:5(16:10).
The artist only needs to create three sizes of wall paper to accommodate everyone's needs. The user should be able to adjust the size of the wall paper with any graphics program such as Photoshop or Paintshop.
If anyone is in need of a free graphics program they can find one at Paint.net
Paint.netis free image and photo editing software for computers that run Windows. It features an intuitive and innovative user interface with support for layers, unlimited undo, special effects, and a wide variety of useful and powerful tools. An active and growing online community provides friendly help, tutorials, and plugins.
It started development as an undergraduate college senior design project mentored by Microsoft, and is currently being maintained by some of the alumni that originally worked on it. Originally intended as a free replacement for the Microsoft Paint software that comes with Windows, it has grown into a powerful yet simple image and photo editor tool. It has been compared to other digital photo editing software packages such as Adobe® Photoshop®, Corel® Paint Shop Pro®, Microsoft Photo Editor, and The GIMP.
If you are interested in Paint.net feel free to visit.