Expert guidence needed...so new, so inexperienced

i’m starting with web design and i have a few major problems that i’m sure most of you could help me with.
first of all, i don’t understand the deal with photos…how is it that on professionally made websites, photos look so crisp and high quality, yet the load time is remarkably short. on my site on which i use jpgs, they look like crap and they’re huge…i’m curious if there’s a particular way to save them and if there’s a particular program…for photos, i use photoshop’s “save for web” function and usually save them at 60% quality because any higher and the files are massive.
basically, i’m curious how pros get their flash sites to load so quickly but all their images are crisp…any tips would be really awesome
thanks
-sean