The following example shows how you can display an error string on the Flex Image control when an image is unable to be loaded.
Full code after the jump.
<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/05/03/displaying-an-error-tool-tip-for-an-image-control-in-flex/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="vertical"
verticalAlign="middle"
backgroundColor="white">
<mx:Image id="img"
source="http://www.helpexamples.com/flash/images/404.gif"
width="160"
height="120"
ioError="img.errorString = event.text;" />
</mx:Application>
View source is enabled in the following example.
The error string only appears if you hover your mouse over the broken image skin.





this is awesome!