Regarding scenes; these were set up so you could have an easy way to move between two completely different segments within a Flash file. However, 98% of the time, you're going to want to use at least one element throughout all your different segments. Say, some navigation buttons or a background image. The problem with scenes is that if you want to move something in all scenes, you have to go into every scene and move it.
It's often easier to place everything on the main timeline, and contain your 'scenes' within movie clips using stop(); and play(); actions, or just laying out your entire movie on the main timline.
Flash is all about economizing your resources, creating something once, and then re-using it as much as possible. However, there's no right or wrong way, and different movies may require different ways to break up movie clips. For more complex actions, you'll likely have movie clips within movie clips within movie clips.
Blue-genie's right about putting your shutter effect into a movie clip in the library and reusing it. You can then space out your images in the main timeline, add another layer over your images, and drop the movie clip onto the timeline where you want it to appear. If you want your background photo to move, you can do it in the timeline, or drop the image into a movie clip and animate it there, then drop it back onto the timeline.
If you're more comfortable with programming you can also call up these actions with Actionscript, or find an image transtion component online somewhere.
I hope this makes sense?
