Checking for an image before calling script

I need to put the following code into my template:

<script type="text/javascript">
var objLink = new myC_Remote.BuyLink();
objLink.LinkContent = "<img src=\"http://www.mydomain.com/images/remote_Print_this_Image_0.gif\" alt=\"Print this Image\" />";
objLink.IsAboveImage = true;
objLink.LinkClass = "field-items";
objLink.Render();
</script>

I need to check that there is an image attached to the node before this is called. How can I check for the existance of a valid field_image before executing this?

I know this is a lame support request, just hoping there is a friendly super-genius around willing to lend some brain cells to a rookie?