Image appears only from root

[eluser]trope[/eluser]
Let's say I have a background image defined in a style sheet as follows:

../css/myimage.php

The image appears fine when I run my default index controller. But when I have to redirect to a different controller, such as:

( user login was invalid, simply return to login and try again )....

http://localhost/resume/index.php/login

Now the image does not display. Does anyone know how I can fix this?

Thanks!