simple computer question

[JaBlue]

i have several images online that I want to print out. Currently they print to be, say 2/3 of a page. I want to stretch them out to print on a full page. I have windows 2000. I tried using paint and setting attribute to 8.5x11" but it messed up because I forgot about margins. I don't know what standard margins are so I'm not going to try agian.

Anyway, whats the easiest way to blow it up so it will print on the full page?