With multi-gigabyte storage drives, stuff below 50MB is a spit in an ocean...
I don't believe it has anything to do with how much space it takes up on the hard disk, but the hassle downloading the larger files on dial-up.
Ok, you are on dial-up, but lets be realistic shall we. It's 2012, those still on dial-up are in large minority, so you can't expect anyone to still base their operations and products on those few that are unfortunate enough to still be on dialup. If we'd be looking on everyone this unfortunate, we'd still be using steam machines and computers with vacuum tubes...