I noticed that when I open a CSS through a browser I see that all my images have some IP prepended to them. It looks like this:
In reality, my CSS is using relative path:
url(/i/pgBg.png)
What happen? What’s causing this? Was my site hacked and some server overwrite rule was added? It seem to affect only CSS, because the images in the page are fine.
Those two IP addresses are registered to Flash Networks (see here and here).
Your CSS is probably being modified by their web acceleration service to point to a cached copy of your images on their servers.
If you didn’t set this up yourself, you will need to consult your server manager or hosting company for more information.
EDIT: Apparently Verizon is/was doing something with that web acceleration service. This may also be relevant.