Export! Do Not Save!

Oh I found this pretty interesting since I'm actually taking the multimedia engineering course this semester. It talks about graphical data compression, too.
But I'm not actually that used with photoshop and any bitmap manipulation software, I'm still not really understanding what's the most optimal solution to each cases.
But at least, i can say that saving file in vector format:
- .ai for adobe illustrator
- .cdr for coreldraw
- .svg for general purpose and inkscape
- .eps, a kind of level-up of svg
Would probably take a much smaller size (in condition that you dont embed or link any bitmap element in it's file)