border-bottom replacement

i am trying to replace the 1px border-bottom style within the .upw-posts article tag with a background graphic image. i tried adding the following to my child theme style.css file:

.upw-posts article {
border-bottom: none !important;
}

.upw-posts footer {
background-image: url(“pageSep.png”) !important;
background-repeat: no-repeat;
}

The line separator goes away but no graphic. Am i correct trying to style this in the footer tag? Im still quite new at this and am getting nowhere fast. Any assistance would be appreciated.

https://ww.wp.xz.cn/plugins/ultimate-posts-widget/