I have developed a web page using windows and it works fine. but when I want to upload in on the web using ubuntu, one image is not shown. here is the css code:
background: url('../img/background/start.jpg') #c0c0c0 bottom center fixed no-repeat;
In ubuntu navigate to the folder and grant all access to all content by:
chmod -R 777 .
If that solves the problem, then you know it's a permission issue.
Note: In general it's not safe to grant all access to all users especially in production.
P.S. another easy way would be just to upload your images on a third party (like amazon S3) as it's a much better practice to host your assets somewhere other than your main server anyway.