Inserting Header Image in 2.71

I’m trying to follow instructions for adding a header image by digging into the code, but am having troubles. I am new to WordPress, and not a pro at HTML. But the directions seem straightforward, somewhat, and I’m still having trouble. Rather than finding the code ‘#header’ and ‘#headerimg’ I found the #page codes below. The only reference to ‘#headerimg’ was at the bottom of the code behind the code <div id, which I thought indicated the end of a page… So I plugged in the name of the image in place of Kubricker.jpg, as instructed, and put the location of the uploaded image in parentheses following bloginfo(), as you can see below, but I can not get the image to appear in the header. Am I missing an important step, plugging in the wrong code, or plugging code in in the wrong place? Also, where should I add the code for the specific pixels/size of the image? … If anyone can help, I’d absolutely appreciate it as I am stuck! Thanks!

#page { background: url(“<?php bloginfo(wp-content/uploads); ?>/images/dreamstime_829439011-<?php bloginfo(wp-content/uploads); ?>.jpg”) repeat-y top; border: none; }
<?php } else { // No sidebar ?>
#page { background: url(“<?php bloginfo(wp-content/uploads); ?>/images/dreamstime_829439011.jpg”) repeat-y top; border: none; }
<?php } ?>