Ok, this is what you do:
-you can see, you CANT change the size on the bottom of your DSi screen.
-But this is SUPER DUPER easy. =P

What to do:
-get on a message, home page, etc.
-Just refresh, then press the refresh button right away.
Btw the screen is supossed to be all white.
-AND you shouldnt do it on your messages list (it wont load fully).
lol thats all you do!