How to set my Nikon D3100 image size recording as 600x400?

How do i set my Nikon D3100 to record photos as 600 x 400 automaticly. Currently, it records at small, at 1980x1000 something like that. Is it possible to set it so that it records photos at 600 x 400 and not 1980 x 1000? This is becoming a pain as if i want to upload the photo, a huge photo like 1980x1000 takes a bunch of time. It would take hours. Please help. Thanks

P.S. And yes, i know there's a retouch menu where i can make it smaller, but when i upload it, it just makes my photos crack alittle. And do i have to do it for every photo?
Is their a setting so i can take photos and it records automatically as 600x400?

You can't. Also, be aware that from a small photo it's already tricky to get a print, from a 600x400 it's i'm, possible.

If you insist, there's a freeware tool, ifranview, that can take a whole folder of images and resize them for you.