Hey Ryan,
Go to components/com_hotspots/views/all/default.php and find
<div id="map_overlay_cont" style="background: url('media/com_hotspots/images/utils/<?php echo $map_overlay_bg; ?>') repeat; border-top: <?php echo $map_overlay_border; ?>; <?php if (HotspotsHelper::getSettings('map_overlay_div', 1) == 0) { echo " display: none;"; } ?>">
change it to
<div id="map_overlay_cont" style="height: 100px; background: url('media/com_hotspots/images/utils/<?php echo $map_overlay_bg; ?>') repeat; border-top: <?php echo $map_overlay_border; ?>; <?php if (HotspotsHelper::getSettings('map_overlay_div', 1) == 0) { echo " display: none;"; } ?>">
for example.
This should do the trick.
Daniel