and then resize it to the power of 2 (256*256) and save it as a .jpg put it in your mission folder and edit your overview so it looks like this
<html>
<head>
<title>Overview</title>
</head>
<body>
<p align="center"><img src="picturename.jpg" width="170" height="150"></p>
</body>
</html>
you'll need to adjust the width and height I just made that up.