On line 143 in your template you have this
img {
height:auto !important;
max-width:100% !important;
-webkit-box-sizing: border-box !important; /* Safari/Chrome, other WebKit */
-moz-box-sizing: border-box !important; /* Firefox, other Gecko */
box-sizing: border-box !important; /* Opera/IE 8+ */
}
the max-width is set to 100% with !important...
In bootstrap-default.css you have this
#map_canvas img {
max-width: none;
}
But since your template has included the max-width definition with !important it always has a higher weight for the css.
Try to change:
#map_canvas img {
max-width: none;
}
to
#map_canvas img {
max-width: none!important;
}
let me know how it goes