在加载背景图像之前设置网页背景颜色

I have a web application, and the background image is a dark color. It's also over 100KB in size. (I don't really appreciate the background image being that big, but that's not anything I can do anything about, or the subject of this question.. In addition it's a JPEG! .. The web design has come from the customer and I have to leave it as it is, despite my protests!)I have a web application, and the background im