SWF vs PNG image


My flash application loaded png images using MovieLoader.loadClip. Some of those png images are now .svg and so in order for the application to render it, I am first getting them converted to swf. I have tried loading the new swf using loadClip and I see that everything works as before.
I am a beginner as far as flash is concerned and need to gauge if there are any limitations/ pros and cons of replacing the png with swf. From my preliminary search I have found that swf is high quality but slow loading. Our requirements are not exactly real-time and so slow loading isnt much of a concern. Are there other technical cons to be aware of when using swf format for every image that is loaded in the application?