I presume that you mean that you have used the SlideShow Maker wizard. Yes. As soon as you have everything on the timeline (do not edit in Storyboard mode), you can edit everything normally. You need to learn how to edit and how to use the effects. PhotoStory is a powerful editing program.
Start with one effect on one photo. Put the playback marker on it and select it. Go to FX tab. Look at the top of the selected clip. There is the filename and the effect. Find the effect and you can modify it.
If you have trouble, post a screen shot and indicate what you are trying to do.