Here is a great tip that can help you avoid a very common mistake made by many inexperienced web site designers. This can make a big difference in how professional your site is perceived.
A common mistake made by many when using background images, especially those backgrounds with a colored left spine is that you are often only viewing the page in the screen resolution to which your monitor is set. I’ve seen page after page where there is a blue spine down the left side, with the center of the page having black text on a white background.
The problem arises when you are looking at your page in screen resolution of only 800×600, which is the most common screen resolution used today. While it is the most common, if you are using a 17″ monitor, you should be using 1024×768 screen resolution, and on a 19″ monitor you should be using 1280×1024 screen res. These are the screen resolution people with larger monitors use on a day-to-day basis.
If your background image is only 800 pixels wide, it may look great on your screen, but what you don’t see is that the blue spine on the left side will start repeating at pixel 801. On a larger monitor, people see the blue spine about 75% of the way across the screen and your black text is now running through that part of the blue spine making your text unreadable.
This primarily occurs on web sites that are using variable width design. In other words the text spacing resizes depending on the resolution of your screen. On websites designed using fixed width tables, this becomes less of an issue. It is very important you check your page in many different screen resolutions.