Problem loading external xml files w/ grahics

I have a problem with xml files I am bringing into Flash MX 2004. The xml files each contain thumbnail images a various locations within the text. The images are jpg and they do show insode Flash, however, the problem is getting them to appear at the right position within the text. The best I’ve been able to do is change the content from xml to xhtml and specify the horizontal and vertical image position. This has worked, but when I change resolution or the browser window size, the images shift a bit from their place and cover the text. I have tried an alignment of absmiddle in addition to the horizontal and vertical position, and it helps a little bit, but not completely. The images still shift.
Does anyone know a way to get around this problem? I am not a Flash expert by any means and would appreciate any help I can get. Thanks!