Swf files are not editable.Whereas fla files are editable. Think of it this way. FLA files are text files that can be created with notepad, word, etc. A swf file is machine code that requires the flash player to interpret it in a browser or AIR to interpret it as an application.
Flash professional and flash catalyst take the text and compile it as a swf file.
Flash pro can import a swf file though and pass it along during the compile process.
It sounds like you are already getting in way deeper than the process I mentioned. The reason for going the flash route is when you need to add code to allow that amination to do things you can not do visually. For example adding random blured dots and move them in a random pattern to make it look like snow. Thats a great use of flash as you are letting the computer do the work for you.
But for a simple slide show where you are showing one image after another with maybe a fade in between, flash is a bit of a side step.
What helps with flash is as you have seen people create templates for slides shows using code. That allow others you just add the images and maybe a few features and run the compiler.
The problem then becomes did the person creating that template do a good enough job? Did they have your best interest at heart? Yes, even flash is suseptable to coders that have alterior motives.
As for being afraid of quicktime, why? Apple has been in business for more years than I can remember back in the 80's anyway. Quicktime is on more PC computers than I probably could count. It's definately on all Mac computers. Its required to export any video from photoshop.
I tell you what though, because you have the state of mind of going down the flash route, I recommend that you repost over on the flash forum(s) As they would have way more answers about flash than you would get here.
I also beleive that Apple has their own forum for anything quicktime related, so that may quench your answers about quicktime.
Good luck and if you have any further questions related to photoshop, feel free to post.