Thanks for your reply.
"Empty cache" sounds good. The change I was looking for still doesn't appear in the browser. I am looking for a white background for my project (http://imatchdesigners.com) and I see the old blue one instead.
SO I tried another approach: Instead of changing the stylesheet to remove the unwanted background image and make the div white (#fff), I just replaced the blue background image with a white one of the same size.
So I exported all the media files, wp-includes, theme files, minify files and custom files.
The old bg image is still there.
I am using the CLoudFlare service. I wonder if that is part of the problem.
Do you have this problem?