.relative1 {
    background-image: url(./doc_test_image.png);
}
.absolute {
    background: url("http://example.com/browser/devtools/client/styleinspector/test/doc_test_image.png");
}
.base64 {
    background: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==');
}