@Mate, I edited my css to the format you said. However the images still aren't coming up. I also deleted the old ones and re-uploaded them. Could it be because they are .png format?
[7 minutes later]
or could my problem be related to this thread: images not showing
If not using hotlink protection, then remove this line from your .htaccess:
RewriteRule .*\.(jpg|jpeg|gif|png|bmp)$ - [F,NC]
however it tells me there is an error with downloading that htaccess file. I disabled all hotlink protection