A basic custom theme can be developed very easily – just create a graphic 250 pixels wide and 500 to 800 pixels tall.  Pick a regular (non custom) Twitter theme that is close to the background color that you are using and then adjust the colors accordingly.  Two examples can be found here:

http://twitter.com/openmk – my twitter page
http://twitter.com/coshrink– my friend Nancy Raulston’s page

Note that this background is optimized for people who use modern laptops and larger screen monitors, capable of browsing at resolutions better (higher) than 800 x 600.  It’s been tested – for example – on a 13″ wide Macbook.  It will look good on most Netbooks … since they use a high resolution to fit an entire page on a relatively small screen.  Where it won’t look good is on older machines/monitors where 800 x 600 is the default resolution … but fewer and fewer people are using this resolution, IMHO.

For a more elaborate background theme, create a visual 1600 wide x 1200 wide.  A background to use as a template exists at this location:


I had nothing to do with this background.  It just provides a nice template you can use to get started.  In most browsers you can right click to bring up a menu and then save background to save the background image.