Your title is inaccurate. This isn't a Flex question at all.
The Images directory would not be downloaded automatically. Only resources referenced by index.html would be retrieved. Otherwise, there's no way for your browser to know that the Images directory or its contents exist!
Sorry for title but many thanks for the answer: it's what I wanted to hear ^^
Listen and what if in the code I set an if branch like
?Both images are dowloaded or just the one choosen by the if?
If you embed the images in your swf, then they are both transfered as part of the package whether you use them or not. The other option is to load images external to the swf at run-time.