@Zynaphix if it helps, this is basically what I am using to display signature images at different sizes based on the screen width (ie so it works with tablets and mobiles):
Code:
<xen:comment>Limiting image sizes in signatures</xen:comment>
<xen:if is="@enableResponsive">
@media (min-width:700px) {
.signature.messageText img {
max-height: 125px !important;
max-width: 550px !important;
}
}
@media (min-width:481px) {
.signature.messageText img {
max-height: 125px;
}
}
</xen:if>
The first part ensures that signatures conform with the max sizes I have specified on my site. The second part it so that images will shrink at smaller screen widths.
Below 481px is narrowResponsiveWidth (as defined in the Responsive section of the ACP) and signatures aren't displayed at all - this is for mobile phone sized screens.
Adjust the sizes and the min-widths as appropriate for your forum.