You can easily see the flash file's individually composed elements and images and remove whatever you want. In fact, you could also edit it on the go as well as saving and converting the results for the subsequentconversion.
Although being able to do all of this would be useless if there wasn't an easy to use interface. Decompile Flash Free Version has that and lets you decompile SWF files as you please even if you are not so tech-savvy.
Decompile Flash Free Version, interestingly enough, removes any flash images or gifs that you find on the internet; something that a lot of us have wanted to do more than once.