I made a small banner in After Effects (150x75) and exported as a low quality swf. When I try to upload, the site rejects it saying that the files size exceeds the limit. the animation is three seconds long.
I have Flash CS3 as part of the bundle, but I'm a noobie to Flash. How can I make the file size smaller?
Why don't you tweak the conversion settings to make it smaller. Lowering the bitrate will make a smaller file. Also, you should be able to change how often the keyframes are added. If you aren't using a seek bar, don't have keyframes added at all. If you are, every 15 frames should be fine. Lastly (reserve for last), lower the frame rate.