Here's A Dumb Question...

removed

You wouldn't believe how long this had wrecked my head.

I thought you just had to use dvdr's, but that would be a total waste, like saving a 3MB video file on a 700MB disc.

It depends on what the file type is - A BIN file's always a lot bigger than an ISO.

If you want to see for yourself, do what I do - Download WinISO using KL (You'd have to "register" it to get past the evaluation restrictions that would restrict you even trying it). The latest version (and a few before it) lets you convert BINs to ISOs - Once you do that, you can see that most ISOs go below 700MB.