Problem changing login image in Canvas mobile version

Community Explorer

I have a problem, searching in the community I found this code to be able to change the login image to that of the institution where I work.

.mobileLogin-Header {
z-index: 1;
background-image: url( !important;
background-position: center;
background-repeat: no-repeat;
background-size: 250px 108px;
min-height: 108px;

It worked perfectly but the problem is that using this simple code created problems in the classrooms. They did not load images, genially for example. (we have CidiLabs installed) Could this be the problem? Has anything similar happened to anyone?

From already thank you very much!