What is the best size for an image to be if you want it to be your myspace background?

To fill the whole background area, and by leaving the image static

What is the best size for an image to be if you want it to be your myspace background?

This is really a choice of aesthetics over what is best. Any size image would work. An image 1600x1200 would ensure that just about everyone could see it without any blank area around it. Of course, people with smaller resolutions will miss seeing the edges of the image.

However, if you want to add a static image that will work for everyone, regardless of their screen resolution, I recommend using a smaller image (like 800x600 or smaller) that has a solid color border around it, so that you can set your background color to match the boarder.

I use this method in my own profile. Click the source link to see my profile for an example.