IE will not load images

IE will not load images

I have a div containing 5 images, for some reason only the 3rd and 5th
image does not show up in IE. They are png image file types. When the page
loads there is a border for the image and a small icon inside the border
with an 'x'. This is only for the latest IE. Works fine in Chrome and
Firefox. Day 4 of cross browser headaches.
<div id="col3"><h4 style="text-align:center;">Affiliations:</h4>
<br>
<img src="./Gallery/sponsorimg/astro.png"
style="align:center;width:150px;height:100px;margin-bottom:45px">
<br>
<img src="./Gallery/sponsorimg/avngr.png"
style="align:center;width:150px;height:100px;margin-bottom:45px">
<br>
<img src="./Gallery/sponsorimg/skulc.png"
style="align:center;width:150px;height:100px;margin-bottom:45px">
<br>
<img src="./Gallery/sponsorimg/sqdgrp.png"
style="align:center;width:150px;height:100px;margin-bottom:45px">
<br>
<img src="./Gallery/sponsorimg/812.png"
style="align:center;width:150px;height:100px;margin-bottom:45px">
<br>
<br>
<br>
<br>
</div>
#col3
{
float: left;
width: 20%;
height: 850px;
margin-left: 3%;
margin-bottom: 10px;
background-color:#fff;
background:url('dpimg4.jpg');
border:double 7px #000000;
-moz-border-radius: 0px;
-webkit-border-radius: 0px;
border-radius: 0px;
}