I've had the same issue as above (only in Safari too). My body tag has a background image, is repeat-x and is used as the background for the whole website. When a user goes to the page in Safari, there is a flash of black on page load. I've searched for ages for a solution to this, but it appears to be an unresolved bug with Safari.
I'ved tried adding "style: background-color: #FFF" to the html and body tags and also tried using the old school "bgcolor: #FFF" - none work.
The only way I could get Safari to behave was to use CSS + jQuery. Give the body a class of "bg-on" in your html and CSS files. In a linked .js file or in the of your html page in tags:
jQuery(function ($) {
$(document).ready(function(){
$('body').removeClass('bg-on');
});//end document ready
/* NOTE (window).load fires when images have been fully loaded */
$(window).load(function() {
$('body').addClass('bg-on');
});//end window load function
});//end jQuery function no conflict mode
What the above does is when the DOM is loaded by the browser, it removes the class from the body, therefore Safari won't show a black background as no background-image is there. Then when the window.load event fires, when all assets have been loaded, the body is given the background image...
It won't affect JS disabled browsers either, as the class of "bg-on" is hardcoded into the html.
Not a particularly elegant solution, but it works for me.