I just opened an animated .gif I did in ImageReady, works fine. No quality problems . Just go to File > Open > Find your image.
You can also import the GIF into your flash MX program. However, expect the same quality of animation if you want it "smooth" like most flash animations, you might have to redo it..
How does opening it in imageready help? I created it in image ready. Do I just open it in flash and then save it as a swf? I have the program but have only tweaked .fla files.
Import the gif using ulead gif animator, remove the frame ( optional ), keep the quality and click save as flash format. This is the easy way to convert gif to flash in less than 10 seconds.