You need not embed, you can give path to the images on the server. like
<mx:Image width="180" source="http://somedomain.com/images/logo.JPG"
id='image'/>
OR, using the id of the image component, you can assign the logo dynamically, like the following
private function onCreationcomplete(e:FlexEvent):void
{
if(client ='xxyy'){
image.source = 'http://somedomain.com/images/xxyy.JPG ';
}
}