Line 24, Column 60: there is no attribute "background". <table width="600" border="0" align="center" background="img/Guitar-Garage.jpg" >
Ok, so how do I get the image in the background and still have it work and validate?

you can do this:

<table width="600" border="0" align="center" style="background-image:url(img/Guitar-Garage.jpg);" >

CSS is the way to do layout and styling. If you use deprecated attributes why are you surprised they don't validate?

The reason it works is browsers have to work with old pages made with that code. (And all the newer pages made with bad coding).