I'm a beginner in Flex so I meet lots of problems for the moment. Currently my problem is when I put a picture on my page with the designer, and when I put 100% for the width,or drag the right side of my picture, or fix this picture on right and left of my screen, only the "mx:image" container is resize, not the picture. As we can see on the following picture, the upper bar keeps its original size.
My problem is just resizing the picture's width in order to take always the whole width of my screen as my background.
I solve the problem by changing mx:image in s:bitmap image.now it is ok