<div class="pollContent">

<div class="custom_pollImage"></div>

.custom_pollImage {
background: url("linktoyourimage") no-repeat;
width: 150px;
height: 150px;
position: absolute;
left: -200px;
}

 .nodeX .custom_pollImage {
background: url("linktoyourimage") no-repeat;
width: 150px;
height: 150px;
position: absolute;
left: -200px;
}

.pollBlock .questionMark {
display: none;
}

<xen:if is="@enableResponsive">
@media (max-width:@maxResponsiveWideWidth) {
.custom_pollImage {
display: none;
}
}

@media (max-width:@maxResponsiveMediumWidth) {
.custom_pollImage {
display:none;
}
}

@media (max-width:@maxResponsiveNarrowWidth) {
.custom_pollImage {
display:none ;
}
}
</xen:if>